!!$ 
!!$              Parallel Sparse BLAS  version 2.2
!!$    (C) Copyright 2006/2007/2008
!!$                       Salvatore Filippone    University of Rome Tor Vergata
!!$                       Alfredo Buttari        University of Rome Tor Vergata
!!$ 
!!$  Redistribution and use in source and binary forms, with or without
!!$  modification, are permitted provided that the following conditions
!!$  are met:
!!$    1. Redistributions of source code must retain the above copyright
!!$       notice, this list of conditions and the following disclaimer.
!!$    2. Redistributions in binary form must reproduce the above copyright
!!$       notice, this list of conditions, and the following disclaimer in the
!!$       documentation and/or other materials provided with the distribution.
!!$    3. The name of the PSBLAS group or the names of its contributors may
!!$       not be used to endorse or promote products derived from this
!!$       software without specific written permission.
!!$ 
!!$  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
!!$  ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
!!$  TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
!!$  PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE PSBLAS GROUP OR ITS CONTRIBUTORS
!!$  BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
!!$  CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
!!$  SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
!!$  INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
!!$  CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
!!$  ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
!!$  POSSIBILITY OF SUCH DAMAGE.
!!$ 
!!$  
!
!  The merge-sort and quicksort routines are implemented in the
!  serial/aux directory
!  References:
!  D. Knuth
!  The Art of Computer Programming, vol. 3
!  Addison-Wesley
!  
!  Aho, Hopcroft, Ullman
!  Data Structures and Algorithms
!  Addison-Wesley
!
module psb_sort_mod
  use psb_const_mod

  ! 
  !  The up/down constant are defined in pairs having 
  !  opposite values. We make use of this fact in the heapsort routine.
  !
  integer, parameter :: psb_sort_up_=1,      psb_sort_down_=-1
  integer, parameter :: psb_lsort_up_=2,     psb_lsort_down_=-2
  integer, parameter :: psb_asort_up_=3,     psb_asort_down_=-3
  integer, parameter :: psb_alsort_up_=4,    psb_alsort_down_=-4
  integer, parameter :: psb_sort_ovw_idx_=0, psb_sort_keep_idx_=1
  integer, parameter :: psb_heap_resize=200

  type psb_int_heap
    integer              :: last, dir
    integer, allocatable :: keys(:)
  end type psb_int_heap
  type psb_int_idx_heap
    integer              :: last, dir
    integer, allocatable :: keys(:)
    integer, allocatable :: idxs(:)
  end type psb_int_idx_heap
  type psb_real_idx_heap
    integer                     :: last, dir
    real(psb_spk_), allocatable :: keys(:)
    integer, allocatable        :: idxs(:)
  end type psb_real_idx_heap
  type psb_double_idx_heap
    integer                     :: last, dir
    real(psb_dpk_), allocatable :: keys(:)
    integer, allocatable        :: idxs(:)
  end type psb_double_idx_heap
  type psb_scomplex_idx_heap
    integer                        :: last, dir
    complex(psb_spk_), allocatable :: keys(:)
    integer, allocatable           :: idxs(:)
  end type psb_scomplex_idx_heap
  type psb_dcomplex_idx_heap
    integer                        :: last, dir
    complex(psb_dpk_), allocatable :: keys(:)
    integer, allocatable           :: idxs(:)
  end type psb_dcomplex_idx_heap

  interface psb_msort
    module procedure imsort, dmsort, zamsort, smsort, camsort
  end interface

  interface psb_msort_unique
    module procedure imsort_u
  end interface

  interface psb_qsort
    module procedure iqsort, sqsort, cqsort, dqsort, zqsort
  end interface

  interface psb_hsort
    module procedure ihsort, shsort, chsort, dhsort, zhsort
  end interface

  interface psb_init_heap
    module procedure psb_init_int_heap, psb_init_int_idx_heap,&
         & psb_init_double_idx_heap, psb_init_dcomplex_idx_heap, &
         & psb_init_real_idx_heap, psb_init_scomplex_idx_heap
  end interface

  interface psb_dump_heap
    module procedure psb_dump_int_heap, psb_dump_int_idx_heap,&
         & psb_dump_real_idx_heap, psb_dump_scomplex_idx_heap, &
         & psb_dump_double_idx_heap, psb_dump_dcomplex_idx_heap
  end interface

  interface psb_howmany_heap
    module procedure psb_howmany_int_heap, psb_howmany_int_idx_heap,&
         & psb_howmany_real_idx_heap, psb_howmany_scomplex_idx_heap,&
         & psb_howmany_double_idx_heap, psb_howmany_dcomplex_idx_heap
  end interface

  interface psb_insert_heap
    module procedure psb_insert_int_heap, psb_insert_int_idx_heap,&
         & psb_insert_real_idx_heap, psb_insert_scomplex_idx_heap,&
         & psb_insert_double_idx_heap, psb_insert_dcomplex_idx_heap
  end interface

  interface psb_heap_get_first
    module procedure psb_int_heap_get_first, psb_int_idx_heap_get_first,&
         & psb_real_idx_heap_get_first, psb_scomplex_idx_heap_get_first,&
         & psb_double_idx_heap_get_first, psb_dcomplex_idx_heap_get_first
  end interface


contains

  subroutine imsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    integer, intent(inout)           :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_msort'
    call psb_erractionsave(err_act)

    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    n = size(x)
 
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (present(flag)) then 
        flag_ = flag
      else 
        flag_ = psb_sort_ovw_idx_
      end if
      select case(flag_) 
      case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
        ! OK keep going
      case default
        call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
        goto 9999
      end select

      call imsrx(n,x,ix,dir_,flag_)
    else
      call imsr(n,x,dir_)
    end if

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine imsort


  subroutine smsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    real(psb_spk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_msort'
    call psb_erractionsave(err_act)

    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    n = size(x)
 
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (present(flag)) then 
        flag_ = flag
      else 
        flag_ = psb_sort_ovw_idx_
      end if
      select case(flag_) 
      case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
        ! OK keep going
      case default
        call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
        goto 9999
      end select

      call smsrx(n,x,ix,dir_,flag_)
    else
      call smsr(n,x,dir_)
    end if

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine smsort

  subroutine dmsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    real(psb_dpk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_msort'
    call psb_erractionsave(err_act)

    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    n = size(x)
 
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (present(flag)) then 
        flag_ = flag
      else 
        flag_ = psb_sort_ovw_idx_
      end if
      select case(flag_) 
      case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
        ! OK keep going
      case default
        call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
        goto 9999
      end select

      call dmsrx(n,x,ix,dir_,flag_)
    else
      call dmsr(n,x,dir_)
    end if

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine dmsort

  subroutine camsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    complex(psb_spk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_msort'
    call psb_erractionsave(err_act)

    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_asort_up_
    end if
    select case(dir_) 
    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    n = size(x)
 
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (present(flag)) then 
        flag_ = flag
      else 
        flag_ = psb_sort_ovw_idx_
      end if
      select case(flag_) 
      case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
        ! OK keep going
      case default
        call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
        goto 9999
      end select

      call camsrx(n,x,ix,dir_,flag_)
    else
      call camsr(n,x,dir_)
    end if

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine camsort

  subroutine zamsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    complex(psb_dpk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_msort'
    call psb_erractionsave(err_act)

    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_asort_up_
    end if
    select case(dir_) 
    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    n = size(x)
 
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (present(flag)) then 
        flag_ = flag
      else 
        flag_ = psb_sort_ovw_idx_
      end if
      select case(flag_) 
      case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
        ! OK keep going
      case default
        call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
        goto 9999
      end select

      call zamsrx(n,x,ix,dir_,flag_)
    else
      call zamsr(n,x,dir_)
    end if

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine zamsort


  subroutine imsort_u(x,nout,dir)
    use psb_error_mod
    implicit none 
    integer, intent(inout)           :: x(:) 
    integer, intent(out)             :: nout
    integer, optional, intent(in)    :: dir
    
    integer  :: dir_, n, err_act
    
    character(len=20)  :: name

    name='psb_msort_u'
    call psb_erractionsave(err_act)

    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    n = size(x)
 
    call imsru(n,x,dir_,nout)
      

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine imsort_u


  subroutine iqsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    integer, intent(inout)           :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_qsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if

    n = size(x)

    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call isrx(n,x,ix,dir_,flag_)
      else
        call isr(n,x,dir_)
      end if
      
    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call iasrx(n,x,ix,dir_,flag_)
      else
        call iasr(n,x,dir_)
      end if
      
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine iqsort


  subroutine sqsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    real(psb_spk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_qsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if

    n = size(x)

    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call ssrx(n,x,ix,dir_,flag_)
      else
        call ssr(n,x,dir_)
      end if
      
    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call sasrx(n,x,ix,dir_,flag_)
      else
        call sasr(n,x,dir_)
      end if
      
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine sqsort

  subroutine dqsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    real(psb_dpk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_qsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if

    n = size(x)

    select case(dir_) 
    case( psb_sort_up_, psb_sort_down_)
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call dsrx(n,x,ix,dir_,flag_)
      else
        call dsr(n,x,dir_)
      end if
      
    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call dasrx(n,x,ix,dir_,flag_)
      else
        call dasr(n,x,dir_)
      end if
      
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine dqsort


  subroutine cqsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    complex(psb_spk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_qsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_lsort_up_
    end if

    n = size(x)

    select case(dir_) 
    case( psb_lsort_up_, psb_lsort_down_)
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call clsrx(n,x,ix,dir_,flag_)
      else
        call clsr(n,x,dir_)
      end if
      
    case( psb_alsort_up_, psb_alsort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call calsrx(n,x,ix,dir_,flag_)
      else
        call calsr(n,x,dir_)
      end if

    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call casrx(n,x,ix,dir_,flag_)
      else
        call casr(n,x,dir_)
      end if
      
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine cqsort


  subroutine zqsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    complex(psb_dpk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, err_act
    
    character(len=20)  :: name

    name='psb_qsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_lsort_up_
    end if

    n = size(x)

    select case(dir_) 
    case( psb_lsort_up_, psb_lsort_down_)
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call zlsrx(n,x,ix,dir_,flag_)
      else
        call zlsr(n,x,dir_)
      end if
      
    case( psb_alsort_up_, psb_alsort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call zalsrx(n,x,ix,dir_,flag_)
      else
        call zalsr(n,x,dir_)
      end if

    case( psb_asort_up_, psb_asort_down_)
      ! OK keep going
      if (present(ix)) then 
        if (size(ix) < n) then 
          call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
          goto 9999
        end if
        
        call zasrx(n,x,ix,dir_,flag_)
      else
        call zasr(n,x,dir_)
      end if
      
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
      
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine zqsort




  subroutine ihsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    integer, intent(inout)           :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer  :: dir_, flag_, n, i, l, err_act,info
    integer  :: key
    integer  :: index
    
    character(len=20)  :: name

    name='psb_hsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    
    select case(dir_)
    case(psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_) 
      ! OK
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select

    n = size(x)

    !
    ! Dirty trick to sort with heaps: if we want 
    ! to sort in place upwards, first we set up a heap so that
    ! we can easily get the LARGEST element, then we take it out 
    ! and put it in the last entry, and so on. 
    ! So,  we invert dir_!
    !
    dir_ = -dir_ 
    
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (flag_==psb_sort_ovw_idx_) then 
        do i=1, n
          ix(i) = i
        end do
      end if
      l = 0
      do i=1, n 
        key   = x(i)
        index = ix(i)
        call psi_insert_int_idx_heap(key,index,l,x,ix,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! '
        end if
      end do
      do i=n, 2, -1 
        call psi_int_idx_heap_get_first(key,index,l,x,ix,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
        ix(i) = index
      end do
    else if (.not.present(ix)) then 
      l = 0
      do i=1, n 
        key   = x(i)
        call psi_insert_int_heap(key,l,x,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! ',l,i
        end if
      end do
      do i=n, 2, -1 
        call psi_int_heap_get_first(key,l,x,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
      end do        
    end if
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine ihsort


  subroutine shsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    real(psb_spk_), intent(inout)    :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer        :: dir_, flag_, n, i, l, err_act,info
    real(psb_spk_) :: key
    integer        :: index
    
    character(len=20)  :: name

    name='psb_hsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    
    select case(dir_)
    case(psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_) 
      ! OK
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select

    n = size(x)

    !
    ! Dirty trick to sort with heaps: if we want 
    ! to sort in place upwards, first we set up a heap so that
    ! we can easily get the LARGEST element, then we take it out 
    ! and put it in the last entry, and so on. 
    ! So,  we invert dir_!
    !
    dir_ = -dir_ 
    
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (flag_==psb_sort_ovw_idx_) then 
        do i=1, n
          ix(i) = i
        end do
      end if
      l = 0
      do i=1, n 
        key   = x(i)
        index = ix(i)
        call psi_insert_real_idx_heap(key,index,l,x,ix,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! '
        end if
      end do
      do i=n, 2, -1 
        call psi_real_idx_heap_get_first(key,index,l,x,ix,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
        ix(i) = index
      end do
    else if (.not.present(ix)) then 
      l = 0
      do i=1, n 
        key   = x(i)
        call psi_insert_real_heap(key,l,x,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! ',l,i
        end if
      end do
      do i=n, 2, -1 
        call psi_real_heap_get_first(key,l,x,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
      end do        
    end if
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine shsort


  subroutine dhsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    real(psb_dpk_), intent(inout)  :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer          :: dir_, flag_, n, i, l, err_act,info
    real(psb_dpk_) :: key
    integer          :: index
    
    character(len=20)  :: name

    name='psb_hsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_sort_up_
    end if
    
    select case(dir_)
    case(psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_) 
      ! OK
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select

    n = size(x)

    !
    ! Dirty trick to sort with heaps: if we want 
    ! to sort in place upwards, first we set up a heap so that
    ! we can easily get the LARGEST element, then we take it out 
    ! and put it in the last entry, and so on. 
    ! So,  we invert dir_!
    !
    dir_ = -dir_ 
    
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (flag_==psb_sort_ovw_idx_) then 
        do i=1, n
          ix(i) = i
        end do
      end if
      l = 0
      do i=1, n 
        key   = x(i)
        index = ix(i)
        call psi_insert_double_idx_heap(key,index,l,x,ix,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! '
        end if
      end do
      do i=n, 2, -1 
        call psi_double_idx_heap_get_first(key,index,l,x,ix,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
        ix(i) = index
      end do
    else if (.not.present(ix)) then 
      l = 0
      do i=1, n 
        key   = x(i)
        call psi_insert_double_heap(key,l,x,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! ',l,i
        end if
      end do
      do i=n, 2, -1 
        call psi_double_heap_get_first(key,l,x,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
      end do        
    end if
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine dhsort


  subroutine chsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    complex(psb_spk_), intent(inout) :: x(:) 
    integer, optional, intent(in)    :: dir, flag
    integer, optional, intent(inout) :: ix(:)
    
    integer           :: dir_, flag_, n, i, l, err_act,info
    complex(psb_spk_) :: key
    integer           :: index
    
    character(len=20) :: name

    name='psb_hsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_asort_up_
    end if
    
    select case(dir_)
    case(psb_asort_up_,psb_asort_down_) 
      ! OK
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
    
    n = size(x)

    !
    ! Dirty trick to sort with heaps: if we want 
    ! to sort in place upwards, first we set up a heap so that
    ! we can easily get the LARGEST element, then we take it out 
    ! and put it in the last entry, and so on. 
    ! So,  we invert dir_!
    !
    dir_ = -dir_ 
    
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (flag_==psb_sort_ovw_idx_) then 
        do i=1, n
          ix(i) = i
        end do
      end if
      l = 0
      do i=1, n 
        key   = x(i)
        index = ix(i)
        call psi_insert_scomplex_idx_heap(key,index,l,x,ix,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! '
        end if
      end do
      do i=n, 2, -1 
        call psi_scomplex_idx_heap_get_first(key,index,l,x,ix,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
        ix(i) = index
      end do
    else if (.not.present(ix)) then 
      l = 0
      do i=1, n 
        key   = x(i)
        call psi_insert_scomplex_heap(key,l,x,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! ',l,i
        end if
      end do
      do i=n, 2, -1 
        call psi_scomplex_heap_get_first(key,l,x,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
      end do        
    end if
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine chsort


  subroutine zhsort(x,ix,dir,flag)
    use psb_error_mod
    implicit none 
    complex(psb_dpk_), intent(inout) :: x(:) 
    integer, optional, intent(in)      :: dir, flag
    integer, optional, intent(inout)   :: ix(:)
    
    integer             :: dir_, flag_, n, i, l, err_act,info
    complex(psb_dpk_) :: key
    integer             :: index
    
    character(len=20)  :: name

    name='psb_hsort'
    call psb_erractionsave(err_act)

    if (present(flag)) then 
      flag_ = flag
    else 
      flag_ = psb_sort_ovw_idx_
    end if
    select case(flag_) 
    case( psb_sort_ovw_idx_, psb_sort_keep_idx_)
      ! OK keep going
    case default
      call psb_errpush(30,name,i_err=(/4,flag_,0,0,0/))
      goto 9999
    end select
    
    if (present(dir)) then 
      dir_ = dir
    else
      dir_= psb_asort_up_
    end if
    
    select case(dir_)
    case(psb_asort_up_,psb_asort_down_) 
      ! OK
    case default
      call psb_errpush(30,name,i_err=(/3,dir_,0,0,0/))
      goto 9999
    end select
    
    n = size(x)

    !
    ! Dirty trick to sort with heaps: if we want 
    ! to sort in place upwards, first we set up a heap so that
    ! we can easily get the LARGEST element, then we take it out 
    ! and put it in the last entry, and so on. 
    ! So,  we invert dir_!
    !
    dir_ = -dir_ 
    
    if (present(ix)) then 
      if (size(ix) < n) then 
        call psb_errpush(35,name,i_err=(/2,size(ix),0,0,0/))
        goto 9999
      end if
      if (flag_==psb_sort_ovw_idx_) then 
        do i=1, n
          ix(i) = i
        end do
      end if
      l = 0
      do i=1, n 
        key   = x(i)
        index = ix(i)
        call psi_insert_dcomplex_idx_heap(key,index,l,x,ix,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! '
        end if
      end do
      do i=n, 2, -1 
        call psi_dcomplex_idx_heap_get_first(key,index,l,x,ix,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
        ix(i) = index
      end do
    else if (.not.present(ix)) then 
      l = 0
      do i=1, n 
        key   = x(i)
        call psi_insert_dcomplex_heap(key,l,x,dir_,info)
        if (l /= i) then 
          write(0,*) 'Mismatch while heapifying ! ',l,i
        end if
      end do
      do i=n, 2, -1 
        call psi_dcomplex_heap_get_first(key,l,x,dir_,info)
        if (l /= i-1) then 
          write(0,*) 'Mismatch while pulling out of heap ',l,i
        end if
        x(i)  = key
      end do        
    end if
    

9999 continue 
    if (err_act == psb_act_abort_) then
      call psb_error()
      return
    end if
  end subroutine zhsort


  function  psb_howmany_int_heap(heap)
    implicit none 
    type(psb_int_heap), intent(in) :: heap
    integer :: psb_howmany_int_heap
    psb_howmany_int_heap = heap%last
  end function psb_howmany_int_heap

  subroutine psb_init_int_heap(heap,info,dir)
    use psb_realloc_mod
    implicit none 
    type(psb_int_heap), intent(inout) :: heap
    integer, intent(out)            :: info
    integer, intent(in), optional   :: dir
    
    info = 0
    heap%last=0
    if (present(dir)) then 
      heap%dir = dir
    else
      heap%dir = psb_sort_up_
    endif
    select case(heap%dir) 
    case (psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_)
      ! ok, do nothing
    case default
      write(0,*) 'Invalid direction, defaulting to psb_sort_up_'
      heap%dir = psb_sort_up_
    end select
    
    call psb_ensure_size(psb_heap_resize,heap%keys,info)
    return
  end subroutine psb_init_int_heap

  subroutine psb_dump_int_heap(iout,heap,info)
    implicit none 
    type(psb_int_heap), intent(in) :: heap
    integer, intent(out)           :: info
    integer, intent(in)            :: iout
    
    info = 0
    if (iout < 0) then
      write(0,*) 'Invalid file '
      info =-1
      return
    end if
    
    write(iout,*) 'Heap direction ',heap%dir
    write(iout,*) 'Heap size      ',heap%last
    if ((heap%last > 0).and.((.not.allocated(heap%keys)).or.&
         & (size(heap%keys)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else
      if (heap%last > 0) then 
        write(iout,*) heap%keys(1:heap%last)
      end if
    end if
  end subroutine psb_dump_int_heap

  subroutine psb_insert_int_heap(key,heap,info)
    use psb_realloc_mod
    implicit none 

    integer, intent(in)               :: key
    type(psb_int_heap), intent(inout) :: heap
    integer, intent(out)              :: info

    info = 0
    if (heap%last < 0) then 
      write(0,*) 'Invalid last in heap ',heap%last
      info = heap%last
      return
    endif

    heap%last = heap%last 
    call psb_ensure_size(heap%last+1,heap%keys,info,addsz=psb_heap_resize)
    if (info /= 0) then 
      write(0,*) 'Memory allocation failure in heap_insert'
      info = -5
      return
    end if
    call  psi_insert_int_heap(key,heap%last,heap%keys,heap%dir,info)

    return
  end subroutine psb_insert_int_heap


  subroutine psb_int_heap_get_first(key,heap,info)
    implicit none 

    type(psb_int_heap), intent(inout) :: heap
    integer, intent(out)              :: key,info
    
    info = 0

    call psi_int_heap_get_first(key,heap%last,heap%keys,heap%dir,info)

    return
  end subroutine psb_int_heap_get_first


  function  psb_howmany_real_idx_heap(heap)
    implicit none 
    type(psb_real_idx_heap), intent(in) :: heap
    integer :: psb_howmany_real_idx_heap
    psb_howmany_real_idx_heap = heap%last
  end function psb_howmany_real_idx_heap

  subroutine psb_init_real_idx_heap(heap,info,dir)
    use psb_realloc_mod
    implicit none 
    type(psb_real_idx_heap), intent(inout) :: heap
    integer, intent(out)            :: info
    integer, intent(in), optional   :: dir
    
    info = 0
    heap%last=0
    if (present(dir)) then 
      heap%dir = dir
    else
      heap%dir = psb_sort_up_
    endif
    select case(heap%dir) 
    case (psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_)
      ! ok, do nothing
    case default
      write(0,*) 'Invalid direction, defaulting to psb_sort_up_'
      heap%dir = psb_sort_up_
    end select
    
    call psb_ensure_size(psb_heap_resize,heap%keys,info)
    call psb_ensure_size(psb_heap_resize,heap%idxs,info)
    return
  end subroutine psb_init_real_idx_heap

  subroutine psb_dump_real_idx_heap(iout,heap,info)
    implicit none 
    type(psb_real_idx_heap), intent(in) :: heap
    integer, intent(out)           :: info
    integer, intent(in)            :: iout
    
    info = 0
    if (iout < 0) then
      write(0,*) 'Invalid file '
      info =-1
      return
    end if
    
    write(iout,*) 'Heap direction ',heap%dir
    write(iout,*) 'Heap size      ',heap%last
    if ((heap%last > 0).and.((.not.allocated(heap%keys)).or.&
         & (size(heap%keys)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else    if ((heap%last > 0).and.((.not.allocated(heap%idxs)).or.&
         & (size(heap%idxs)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else
      if (heap%last > 0) then 
        write(iout,*) heap%keys(1:heap%last)
        write(iout,*) heap%idxs(1:heap%last)
      end if
    end if
  end subroutine psb_dump_real_idx_heap

  subroutine psb_insert_real_idx_heap(key,index,heap,info)
    use psb_realloc_mod
    implicit none 

    real(psb_spk_), intent(in)      :: key
    integer, intent(in)               :: index
    type(psb_real_idx_heap), intent(inout) :: heap
    integer, intent(out)              :: info

    info = 0
    if (heap%last < 0) then 
      write(0,*) 'Invalid last in heap ',heap%last
      info = heap%last
      return
    endif

    call psb_ensure_size(heap%last+1,heap%keys,info,addsz=psb_heap_resize)
    if (info == 0) &
         & call psb_ensure_size(heap%last+1,heap%idxs,info,addsz=psb_heap_resize)
    if (info /= 0) then 
      write(0,*) 'Memory allocation failure in heap_insert'
      info = -5
      return
    end if
    
    call psi_insert_real_idx_heap(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_insert_real_idx_heap

  subroutine psb_real_idx_heap_get_first(key,index,heap,info)
    implicit none 

    type(psb_real_idx_heap), intent(inout) :: heap
    integer, intent(out)              :: index,info
    real(psb_spk_), intent(out)     :: key
    
    info = 0

    call psi_real_idx_heap_get_first(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_real_idx_heap_get_first


  function  psb_howmany_double_idx_heap(heap)
    implicit none 
    type(psb_double_idx_heap), intent(in) :: heap
    integer :: psb_howmany_double_idx_heap
    psb_howmany_double_idx_heap = heap%last
  end function psb_howmany_double_idx_heap

  subroutine psb_init_double_idx_heap(heap,info,dir)
    use psb_realloc_mod
    implicit none 
    type(psb_double_idx_heap), intent(inout) :: heap
    integer, intent(out)            :: info
    integer, intent(in), optional   :: dir
    
    info = 0
    heap%last=0
    if (present(dir)) then 
      heap%dir = dir
    else
      heap%dir = psb_sort_up_
    endif
    select case(heap%dir) 
    case (psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_)
      ! ok, do nothing
    case default
      write(0,*) 'Invalid direction, defaulting to psb_sort_up_'
      heap%dir = psb_sort_up_
    end select
    
    call psb_ensure_size(psb_heap_resize,heap%keys,info)
    call psb_ensure_size(psb_heap_resize,heap%idxs,info)
    return
  end subroutine psb_init_double_idx_heap

  subroutine psb_dump_double_idx_heap(iout,heap,info)
    implicit none 
    type(psb_double_idx_heap), intent(in) :: heap
    integer, intent(out)           :: info
    integer, intent(in)            :: iout
    
    info = 0
    if (iout < 0) then
      write(0,*) 'Invalid file '
      info =-1
      return
    end if
    
    write(iout,*) 'Heap direction ',heap%dir
    write(iout,*) 'Heap size      ',heap%last
    if ((heap%last > 0).and.((.not.allocated(heap%keys)).or.&
         & (size(heap%keys)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else    if ((heap%last > 0).and.((.not.allocated(heap%idxs)).or.&
         & (size(heap%idxs)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else
      if (heap%last > 0) then 
        write(iout,*) heap%keys(1:heap%last)
        write(iout,*) heap%idxs(1:heap%last)
      end if
    end if
  end subroutine psb_dump_double_idx_heap

  subroutine psb_insert_double_idx_heap(key,index,heap,info)
    use psb_realloc_mod
    implicit none 

    real(psb_dpk_), intent(in)      :: key
    integer, intent(in)               :: index
    type(psb_double_idx_heap), intent(inout) :: heap
    integer, intent(out)              :: info

    info = 0
    if (heap%last < 0) then 
      write(0,*) 'Invalid last in heap ',heap%last
      info = heap%last
      return
    endif

    call psb_ensure_size(heap%last+1,heap%keys,info,addsz=psb_heap_resize)
    if (info == 0) &
         & call psb_ensure_size(heap%last+1,heap%idxs,info,addsz=psb_heap_resize)
    if (info /= 0) then 
      write(0,*) 'Memory allocation failure in heap_insert'
      info = -5
      return
    end if
    
    call psi_insert_double_idx_heap(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_insert_double_idx_heap

  subroutine psb_double_idx_heap_get_first(key,index,heap,info)
    implicit none 

    type(psb_double_idx_heap), intent(inout) :: heap
    integer, intent(out)              :: index,info
    real(psb_dpk_), intent(out)     :: key
    
    info = 0

    call psi_double_idx_heap_get_first(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_double_idx_heap_get_first

  function  psb_howmany_int_idx_heap(heap)
    implicit none 
    type(psb_int_idx_heap), intent(in) :: heap
    integer :: psb_howmany_int_idx_heap
    psb_howmany_int_idx_heap = heap%last
  end function psb_howmany_int_idx_heap

  subroutine psb_init_int_idx_heap(heap,info,dir)
    use psb_realloc_mod
    implicit none 
    type(psb_int_idx_heap), intent(inout) :: heap
    integer, intent(out)            :: info
    integer, intent(in), optional   :: dir
    
    info = 0
    heap%last=0
    if (present(dir)) then 
      heap%dir = dir
    else
      heap%dir = psb_sort_up_
    endif
    select case(heap%dir) 
    case (psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_)
      ! ok, do nothing
    case default
      write(0,*) 'Invalid direction, defaulting to psb_sort_up_'
      heap%dir = psb_sort_up_
    end select
    
    call psb_ensure_size(psb_heap_resize,heap%keys,info)
    call psb_ensure_size(psb_heap_resize,heap%idxs,info)
    return
  end subroutine psb_init_int_idx_heap

  subroutine psb_dump_int_idx_heap(iout,heap,info)
    implicit none 
    type(psb_int_idx_heap), intent(in) :: heap
    integer, intent(out)           :: info
    integer, intent(in)            :: iout
    
    info = 0
    if (iout < 0) then
      write(0,*) 'Invalid file '
      info =-1
      return
    end if
    
    write(iout,*) 'Heap direction ',heap%dir
    write(iout,*) 'Heap size      ',heap%last
    if ((heap%last > 0).and.((.not.allocated(heap%keys)).or.&
         & (size(heap%keys)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else    if ((heap%last > 0).and.((.not.allocated(heap%idxs)).or.&
         & (size(heap%idxs)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else
      if (heap%last > 0) then 
        write(iout,*) heap%keys(1:heap%last)
        write(iout,*) heap%idxs(1:heap%last)
      end if
    end if
  end subroutine psb_dump_int_idx_heap

  subroutine psb_insert_int_idx_heap(key,index,heap,info)
    use psb_realloc_mod
    implicit none 

    integer, intent(in)                   :: key
    integer, intent(in)                   :: index
    type(psb_int_idx_heap), intent(inout) :: heap
    integer, intent(out)                  :: info

    info = 0
    if (heap%last < 0) then 
      write(0,*) 'Invalid last in heap ',heap%last
      info = heap%last
      return
    endif

    call psb_ensure_size(heap%last+1,heap%keys,info,addsz=psb_heap_resize)
    if (info == 0) &
         & call psb_ensure_size(heap%last+1,heap%idxs,info,addsz=psb_heap_resize)
    if (info /= 0) then 
      write(0,*) 'Memory allocation failure in heap_insert'
      info = -5
      return
    end if

    call psi_insert_int_idx_heap(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_insert_int_idx_heap

  subroutine psb_int_idx_heap_get_first(key,index,heap,info)
    implicit none 

    type(psb_int_idx_heap), intent(inout) :: heap
    integer, intent(out)                  :: index,info
    integer, intent(out)                  :: key
    
    info = 0
    
    call psi_int_idx_heap_get_first(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_int_idx_heap_get_first



  function  psb_howmany_scomplex_idx_heap(heap)
    implicit none 
    type(psb_scomplex_idx_heap), intent(in) :: heap
    integer :: psb_howmany_scomplex_idx_heap
    psb_howmany_scomplex_idx_heap = heap%last
  end function psb_howmany_scomplex_idx_heap

  subroutine psb_init_scomplex_idx_heap(heap,info,dir)
    use psb_realloc_mod
    implicit none 
    type(psb_scomplex_idx_heap), intent(inout) :: heap
    integer, intent(out)            :: info
    integer, intent(in), optional   :: dir
    
    info = 0
    heap%last=0
    if (present(dir)) then 
      heap%dir = dir
    else
      heap%dir = psb_sort_up_
    endif
    select case(heap%dir) 
!!$    case (psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_)
    case (psb_asort_up_,psb_asort_down_)
      ! ok, do nothing
    case default
      write(0,*) 'Invalid direction, defaulting to psb_sort_up_'
      heap%dir = psb_asort_up_
    end select
    
    call psb_ensure_size(psb_heap_resize,heap%keys,info)
    call psb_ensure_size(psb_heap_resize,heap%idxs,info)
    return
  end subroutine psb_init_scomplex_idx_heap

  subroutine psb_dump_scomplex_idx_heap(iout,heap,info)
    implicit none 
    type(psb_scomplex_idx_heap), intent(in) :: heap
    integer, intent(out)           :: info
    integer, intent(in)            :: iout
    
    info = 0
    if (iout < 0) then
      write(0,*) 'Invalid file '
      info =-1
      return
    end if
    
    write(iout,*) 'Heap direction ',heap%dir
    write(iout,*) 'Heap size      ',heap%last
    if ((heap%last > 0).and.((.not.allocated(heap%keys)).or.&
         & (size(heap%keys)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else    if ((heap%last > 0).and.((.not.allocated(heap%idxs)).or.&
         & (size(heap%idxs)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else
      if (heap%last > 0) then 
        write(iout,*) heap%keys(1:heap%last)
        write(iout,*) heap%idxs(1:heap%last)
      end if
    end if
  end subroutine psb_dump_scomplex_idx_heap

  subroutine psb_insert_scomplex_idx_heap(key,index,heap,info)
    use psb_realloc_mod
    implicit none 

    complex(psb_spk_), intent(in)              :: key
    integer, intent(in)                        :: index
    type(psb_scomplex_idx_heap), intent(inout) :: heap
    integer, intent(out)                       :: info

    info = 0
    if (heap%last < 0) then 
      write(0,*) 'Invalid last in heap ',heap%last
      info = heap%last
      return
    endif

    call psb_ensure_size(heap%last+1,heap%keys,info,addsz=psb_heap_resize)
    if (info == 0) &
         & call psb_ensure_size(heap%last+1,heap%idxs,info,addsz=psb_heap_resize)
    if (info /= 0) then 
      write(0,*) 'Memory allocation failure in heap_insert'
      info = -5
      return
    end if
    call psi_insert_scomplex_idx_heap(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)
    
    return
  end subroutine psb_insert_scomplex_idx_heap

  subroutine psb_scomplex_idx_heap_get_first(key,index,heap,info)
    implicit none 

    type(psb_scomplex_idx_heap), intent(inout) :: heap
    integer, intent(out)                       :: index,info
    complex(psb_spk_), intent(out)           :: key
    
    
    info = 0
    
    call psi_scomplex_idx_heap_get_first(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_scomplex_idx_heap_get_first



  function  psb_howmany_dcomplex_idx_heap(heap)
    implicit none 
    type(psb_dcomplex_idx_heap), intent(in) :: heap
    integer :: psb_howmany_dcomplex_idx_heap
    psb_howmany_dcomplex_idx_heap = heap%last
  end function psb_howmany_dcomplex_idx_heap

  subroutine psb_init_dcomplex_idx_heap(heap,info,dir)
    use psb_realloc_mod
    implicit none 
    type(psb_dcomplex_idx_heap), intent(inout) :: heap
    integer, intent(out)            :: info
    integer, intent(in), optional   :: dir
    
    info = 0
    heap%last=0
    if (present(dir)) then 
      heap%dir = dir
    else
      heap%dir = psb_sort_up_
    endif
    select case(heap%dir) 
!!$    case (psb_sort_up_,psb_sort_down_,psb_asort_up_,psb_asort_down_)
    case (psb_asort_up_,psb_asort_down_)
      ! ok, do nothing
    case default
      write(0,*) 'Invalid direction, defaulting to psb_sort_up_'
      heap%dir = psb_asort_up_
    end select
    
    call psb_ensure_size(psb_heap_resize,heap%keys,info)
    call psb_ensure_size(psb_heap_resize,heap%idxs,info)
    return
  end subroutine psb_init_dcomplex_idx_heap

  subroutine psb_dump_dcomplex_idx_heap(iout,heap,info)
    implicit none 
    type(psb_dcomplex_idx_heap), intent(in) :: heap
    integer, intent(out)           :: info
    integer, intent(in)            :: iout
    
    info = 0
    if (iout < 0) then
      write(0,*) 'Invalid file '
      info =-1
      return
    end if
    
    write(iout,*) 'Heap direction ',heap%dir
    write(iout,*) 'Heap size      ',heap%last
    if ((heap%last > 0).and.((.not.allocated(heap%keys)).or.&
         & (size(heap%keys)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else    if ((heap%last > 0).and.((.not.allocated(heap%idxs)).or.&
         & (size(heap%idxs)<heap%last))) then
      write(iout,*) 'Inconsistent size/allocation status!!'
    else
      if (heap%last > 0) then 
        write(iout,*) heap%keys(1:heap%last)
        write(iout,*) heap%idxs(1:heap%last)
      end if
    end if
  end subroutine psb_dump_dcomplex_idx_heap

  subroutine psb_insert_dcomplex_idx_heap(key,index,heap,info)
    use psb_realloc_mod
    implicit none 

    complex(psb_dpk_), intent(in)            :: key
    integer, intent(in)                        :: index
    type(psb_dcomplex_idx_heap), intent(inout) :: heap
    integer, intent(out)                       :: info

    info = 0
    if (heap%last < 0) then 
      write(0,*) 'Invalid last in heap ',heap%last
      info = heap%last
      return
    endif

    call psb_ensure_size(heap%last+1,heap%keys,info,addsz=psb_heap_resize)
    if (info == 0) &
         & call psb_ensure_size(heap%last+1,heap%idxs,info,addsz=psb_heap_resize)
    if (info /= 0) then 
      write(0,*) 'Memory allocation failure in heap_insert'
      info = -5
      return
    end if
    call psi_insert_dcomplex_idx_heap(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)
    
    return
  end subroutine psb_insert_dcomplex_idx_heap

  subroutine psb_dcomplex_idx_heap_get_first(key,index,heap,info)
    implicit none 

    type(psb_dcomplex_idx_heap), intent(inout) :: heap
    integer, intent(out)                       :: index,info
    complex(psb_dpk_), intent(out)           :: key
    
    
    info = 0
    
    call psi_dcomplex_idx_heap_get_first(key,index,&
         & heap%last,heap%keys,heap%idxs,heap%dir,info)

    return
  end subroutine psb_dcomplex_idx_heap_get_first


  
  !
  ! These are packaged so that they can be used to implement 
  ! a heapsort, should the need arise
  !
  
  
  subroutine psi_insert_int_heap(key,last,heap,dir,info)
    implicit none 

    !  
    ! Input: 
    !   key:  the new value
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   dir:  sorting direction

    integer, intent(in)     :: key,dir
    integer, intent(inout)  :: heap(:),last
    integer, intent(out)    :: info
    integer                 :: i, i2
    integer                 :: temp

    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif
    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
    i       = last
    heap(i) = key
    
    select case(dir)
    case (psb_sort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) < heap(i2)) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) > heap(i2)) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_int_heap


  subroutine psi_int_heap_get_first(key,last,heap,dir,info)
    implicit none 

    integer, intent(inout)  :: key,last
    integer, intent(in)     :: dir
    integer, intent(inout)  :: heap(:)
    integer, intent(out)    :: info
    
    integer                 :: i, j
    integer                 :: temp

    
    info = 0
    if (last <= 0) then 
      key  = 0
      info = -1
      return
    endif

    key     = heap(1)
    heap(1) = heap(last)
    last    = last - 1

    select case(dir)
    case (psb_sort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) < heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) > heap(j)) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) > heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) < heap(j)) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if
        
        if (abs(heap(i)) < abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_int_heap_get_first


 
  subroutine psi_insert_real_heap(key,last,heap,dir,info)
    implicit none 

    !  
    ! Input: 
    !   key:  the new value
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   dir:  sorting direction

    real(psb_spk_), intent(in)    :: key
    integer, intent(in)           :: dir
    real(psb_spk_), intent(inout) :: heap(:)
    integer, intent(inout)        :: last
    integer, intent(out)          :: info
    integer                       :: i, i2
    real(psb_spk_)                :: temp

    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif
    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
    i       = last
    heap(i) = key
    
    select case(dir)
    case (psb_sort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) < heap(i2)) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) > heap(i2)) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_real_heap


  subroutine psi_real_heap_get_first(key,last,heap,dir,info)
    implicit none 

    real(psb_spk_), intent(inout) :: key
    integer, intent(inout)        :: last
    integer, intent(in)           :: dir
    real(psb_spk_), intent(inout) :: heap(:)
    integer, intent(out)          :: info
    
    integer               :: i, j
    real(psb_spk_)        :: temp

    
    info = 0
    if (last <= 0) then 
      key  = 0
      info = -1
      return
    endif

    key     = heap(1)
    heap(1) = heap(last)
    last    = last - 1

    select case(dir)
    case (psb_sort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) < heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) > heap(j)) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) > heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) < heap(j)) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if
        
        if (abs(heap(i)) < abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_real_heap_get_first

   
  subroutine psi_insert_double_heap(key,last,heap,dir,info)
    implicit none 

    !  
    ! Input: 
    !   key:  the new value
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   dir:  sorting direction

    real(psb_dpk_), intent(in)    :: key
    integer, intent(in)             :: dir
    real(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(inout)          :: last
    integer, intent(out)            :: info
    integer                         :: i, i2
    real(psb_dpk_)                :: temp

    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif
    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
    i       = last
    heap(i) = key
    
    select case(dir)
    case (psb_sort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) < heap(i2)) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) > heap(i2)) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_double_heap


  subroutine psi_double_heap_get_first(key,last,heap,dir,info)
    implicit none 

    real(psb_dpk_), intent(inout) :: key
    integer, intent(inout)          :: last
    integer, intent(in)             :: dir
    real(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(out)            :: info
    
    integer                 :: i, j
    real(psb_dpk_)        :: temp

    
    info = 0
    if (last <= 0) then 
      key  = 0
      info = -1
      return
    endif

    key     = heap(1)
    heap(1) = heap(last)
    last    = last - 1

    select case(dir)
    case (psb_sort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) < heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) > heap(j)) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) > heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) < heap(j)) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if
        
        if (abs(heap(i)) < abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_double_heap_get_first


  
  
  subroutine psi_insert_scomplex_heap(key,last,heap,dir,info)
    implicit none 

    !  
    ! Input: 
    !   key:  the new value
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   dir:  sorting direction

    complex(psb_spk_), intent(in)    :: key
    integer, intent(in)              :: dir
    complex(psb_spk_), intent(inout) :: heap(:)
    integer, intent(inout)           :: last
    integer, intent(out)             :: info
    integer                          :: i, i2
    complex(psb_spk_)                :: temp

    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif
    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
    i       = last
    heap(i) = key
    
    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) < heap(i2)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) > heap(i2)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do

    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_scomplex_heap


  subroutine psi_scomplex_heap_get_first(key,last,heap,dir,info)
    implicit none 

    complex(psb_spk_), intent(inout) :: key
    integer, intent(inout)           :: last
    integer, intent(in)              :: dir
    complex(psb_spk_), intent(inout) :: heap(:)
    integer, intent(out)             :: info
    
    integer                  :: i, j
    complex(psb_spk_)        :: temp

    
    info = 0
    if (last <= 0) then 
      key  = 0
      info = -1
      return
    endif

    key     = heap(1)
    heap(1) = heap(last)
    last    = last - 1

    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) < heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) > heap(j)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) > heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) < heap(j)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if
        
        if (abs(heap(i)) < abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_scomplex_heap_get_first

  
  subroutine psi_insert_dcomplex_heap(key,last,heap,dir,info)
    implicit none 

    !  
    ! Input: 
    !   key:  the new value
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   dir:  sorting direction

    complex(psb_dpk_), intent(in)    :: key
    integer, intent(in)                :: dir
    complex(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(inout)             :: last
    integer, intent(out)               :: info
    integer                            :: i, i2
    complex(psb_dpk_)                :: temp

    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif
    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
    i       = last
    heap(i) = key
    
    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) < heap(i2)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) > heap(i2)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do

    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_dcomplex_heap


  subroutine psi_dcomplex_heap_get_first(key,last,heap,dir,info)
    implicit none 

    complex(psb_dpk_), intent(inout) :: key
    integer, intent(inout)             :: last
    integer, intent(in)                :: dir
    complex(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(out)               :: info
    
    integer                    :: i, j
    complex(psb_dpk_)        :: temp

    
    info = 0
    if (last <= 0) then 
      key  = 0
      info = -1
      return
    endif

    key     = heap(1)
    heap(1) = heap(last)
    last    = last - 1

    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) < heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) > heap(j)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) > heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) < heap(j)) then 
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if
        
        if (abs(heap(i)) < abs(heap(j))) then 
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_dcomplex_heap_get_first




  subroutine psi_insert_int_idx_heap(key,index,last,heap,idxs,dir,info)

    implicit none 
    !  
    ! Input: 
    !   key:  the new value
    !   index: the new index
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   idxs: the indices
    !   dir:  sorting direction

    integer, intent(in)     :: key
    integer, intent(in)     :: index,dir
    integer, intent(inout)  :: heap(:),last
    integer, intent(inout)  :: idxs(:)
    integer, intent(out)    :: info
    integer                 :: i, i2, itemp
    integer                 :: temp 
    
    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif

    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
      
    i       = last
    heap(i) = key
    idxs(i) = index

    select case(dir)
    case (psb_sort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) < heap(i2)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) > heap(i2)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      
    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_int_idx_heap

  subroutine psi_int_idx_heap_get_first(key,index,last,heap,idxs,dir,info)
    implicit none 

    integer, intent(inout) :: heap(:)
    integer, intent(out)   :: index,info
    integer, intent(inout) :: last,idxs(:)
    integer, intent(in)    :: dir
    integer, intent(out)   :: key
    
    integer                :: i, j,itemp
    integer                :: temp

    info = 0
    if (last <= 0) then 
      key   = 0
      index = 0
      info  = -1
      return
    endif

    key     = heap(1)
    index   = idxs(1)
    heap(1) = heap(last)
    idxs(1) = idxs(last)
    last    = last - 1

    select case(dir)
    case (psb_sort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) < heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) > heap(j)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) > heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) < heap(j)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) < abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_int_idx_heap_get_first

  subroutine psi_insert_real_idx_heap(key,index,last,heap,idxs,dir,info)

    implicit none 
    !  
    ! Input: 
    !   key:  the new value
    !   index: the new index
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   idxs: the indices
    !   dir:  sorting direction

    real(psb_spk_), intent(in)     :: key
    integer, intent(in)            :: index,dir
    real(psb_spk_), intent(inout)  :: heap(:)
    integer, intent(inout)         :: idxs(:),last
    integer, intent(out)           :: info
    integer                        :: i, i2, itemp
    real(psb_spk_)                 :: temp 
    
    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif

    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
      
    i       = last
    heap(i) = key
    idxs(i) = index

    select case(dir)
    case (psb_sort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) < heap(i2)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) > heap(i2)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      
    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_real_idx_heap

  subroutine psi_real_idx_heap_get_first(key,index,last,heap,idxs,dir,info)
    implicit none 

    real(psb_spk_), intent(inout) :: heap(:)
    integer, intent(out)          :: index,info
    integer, intent(inout)        :: last,idxs(:)
    integer, intent(in)           :: dir
    real(psb_spk_), intent(out)   :: key
    
    integer                       :: i, j,itemp
    real(psb_spk_)                :: temp

    info = 0
    if (last <= 0) then 
      key   = 0
      index = 0
      info  = -1
      return
    endif

    key     = heap(1)
    index   = idxs(1)
    heap(1) = heap(last)
    idxs(1) = idxs(last)
    last    = last - 1

    select case(dir)
    case (psb_sort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) < heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) > heap(j)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) > heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) < heap(j)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) < abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_real_idx_heap_get_first


  subroutine psi_insert_double_idx_heap(key,index,last,heap,idxs,dir,info)

    implicit none 
    !  
    ! Input: 
    !   key:  the new value
    !   index: the new index
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   idxs: the indices
    !   dir:  sorting direction

    real(psb_dpk_), intent(in)     :: key
    integer, intent(in)              :: index,dir
    real(psb_dpk_), intent(inout)  :: heap(:)
    integer, intent(inout)           :: idxs(:),last
    integer, intent(out)             :: info
    integer                          :: i, i2, itemp
    real(psb_dpk_)                 :: temp 
    
    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif

    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
      
    i       = last
    heap(i) = key
    idxs(i) = index

    select case(dir)
    case (psb_sort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) < heap(i2)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (heap(i) > heap(i2)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      
    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_double_idx_heap

  subroutine psi_double_idx_heap_get_first(key,index,last,heap,idxs,dir,info)
    implicit none 

    real(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(out)            :: index,info
    integer, intent(inout)          :: last,idxs(:)
    integer, intent(in)             :: dir
    real(psb_dpk_), intent(out)   :: key
    
    integer                         :: i, j,itemp
    real(psb_dpk_)                :: temp

    info = 0
    if (last <= 0) then 
      key   = 0
      index = 0
      info  = -1
      return
    endif

    key     = heap(1)
    index   = idxs(1)
    heap(1) = heap(last)
    idxs(1) = idxs(last)
    last    = last - 1

    select case(dir)
    case (psb_sort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) < heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) > heap(j)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_sort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (heap(2*i) > heap(2*i+1)) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (heap(i) < heap(j)) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) < abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_double_idx_heap_get_first


  subroutine psi_insert_scomplex_idx_heap(key,index,last,heap,idxs,dir,info)

    implicit none 
    !  
    ! Input: 
    !   key:  the new value
    !   index: the new index
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   idxs: the indices
    !   dir:  sorting direction

    complex(psb_spk_), intent(in)    :: key
    integer, intent(in)              :: index,dir
    complex(psb_spk_), intent(inout) :: heap(:)
    integer, intent(inout)           :: idxs(:),last
    integer, intent(out)             :: info
    integer                          :: i, i2, itemp
    complex(psb_spk_)                :: temp 
    
    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif

    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
      
    i       = last
    heap(i) = key
    idxs(i) = index

    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) < heap(i2)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(i2)
!!$          idxs(i2) = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp 
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) > heap(i2)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(i2)
!!$          idxs(i2) = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp 
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do
      
    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_scomplex_idx_heap

  subroutine psi_scomplex_idx_heap_get_first(key,index,last,heap,idxs,dir,info)
    implicit none 

    complex(psb_spk_), intent(inout) :: heap(:)
    integer, intent(out)             :: index,info
    integer, intent(inout)           :: last,idxs(:)
    integer, intent(in)              :: dir
    complex(psb_spk_), intent(out)   :: key
    
    integer                          :: i, j, itemp
    complex(psb_spk_)                :: temp

    info = 0
    if (last <= 0) then 
      key   = 0
      index = 0
      info  = -1
      return
    endif

    key     = heap(1)
    index   = idxs(1)
    heap(1) = heap(last)
    idxs(1) = idxs(last)
    last    = last - 1

    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) < heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) > heap(j)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(j)
!!$          idxs(j)  = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp 
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) > heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) < heap(j)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(j)
!!$          idxs(j)  = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp 
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) < abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_scomplex_idx_heap_get_first


  subroutine psi_insert_dcomplex_idx_heap(key,index,last,heap,idxs,dir,info)

    implicit none 
    !  
    ! Input: 
    !   key:  the new value
    !   index: the new index
    !   last: pointer to the last occupied element in heap
    !   heap: the heap
    !   idxs: the indices
    !   dir:  sorting direction

    complex(psb_dpk_), intent(in)    :: key
    integer, intent(in)                :: index,dir
    complex(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(inout)             :: idxs(:),last
    integer, intent(out)               :: info
    integer                            :: i, i2, itemp
    complex(psb_dpk_)                :: temp 
    
    info = 0
    if (last < 0) then 
      write(0,*) 'Invalid last in heap ',last
      info = last
      return
    endif

    last    = last + 1
    if (last > size(heap)) then 
      write(0,*) 'out of bounds '
      info = -1
      return
    end if
      
    i       = last
    heap(i) = key
    idxs(i) = index

    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) < heap(i2)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(i2)
!!$          idxs(i2) = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp 
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      do 
!!$        if (i<=1) exit
!!$        i2 = i/2
!!$        if (heap(i) > heap(i2)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(i2)
!!$          idxs(i2) = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(i2)
!!$          heap(i2) = temp 
!!$          i        = i2
!!$        else
!!$          exit
!!$        end if
!!$      end do
      
    case (psb_asort_up_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) < abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp
          i        = i2
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      do 
        if (i<=1) exit
        i2 = i/2
        if (abs(heap(i)) > abs(heap(i2))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(i2)
          idxs(i2) = itemp
          temp     = heap(i)
          heap(i)  = heap(i2)
          heap(i2) = temp 
          i        = i2
        else
          exit
        end if
      end do
      

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_insert_dcomplex_idx_heap

  subroutine psi_dcomplex_idx_heap_get_first(key,index,last,heap,idxs,dir,info)
    implicit none 

    complex(psb_dpk_), intent(inout) :: heap(:)
    integer, intent(out)               :: index,info
    integer, intent(inout)             :: last,idxs(:)
    integer, intent(in)                :: dir
    complex(psb_dpk_), intent(out)   :: key
    
    integer                            :: i, j, itemp
    complex(psb_dpk_)                :: temp

    info = 0
    if (last <= 0) then 
      key   = 0
      index = 0
      info  = -1
      return
    endif

    key     = heap(1)
    index   = idxs(1)
    heap(1) = heap(last)
    idxs(1) = idxs(last)
    last    = last - 1

    select case(dir)
!!$    case (psb_sort_up_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) < heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) > heap(j)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(j)
!!$          idxs(j)  = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp 
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do
!!$      
!!$          
!!$    case (psb_sort_down_)
!!$
!!$      i = 1
!!$      do 
!!$        if (i > (last/2)) exit
!!$        if ( (heap(2*i) > heap(2*i+1)) .or.&
!!$             & (2*i == last)) then 
!!$          j = 2*i
!!$        else
!!$          j = 2*i + 1
!!$        end if
!!$
!!$        if (heap(i) < heap(j)) then 
!!$          itemp    = idxs(i)
!!$          idxs(i)  = idxs(j)
!!$          idxs(j)  = itemp
!!$          temp     = heap(i)
!!$          heap(i)  = heap(j)
!!$          heap(j)  = temp 
!!$          i        = j 
!!$        else
!!$          exit
!!$        end if
!!$      end do

    case (psb_asort_up_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) < abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) > abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do
      
          
    case (psb_asort_down_)

      i = 1
      do 
        if (i > (last/2)) exit
        if ( (abs(heap(2*i)) > abs(heap(2*i+1))) .or.&
             & (2*i == last)) then 
          j = 2*i
        else
          j = 2*i + 1
        end if

        if (abs(heap(i)) < abs(heap(j))) then 
          itemp    = idxs(i)
          idxs(i)  = idxs(j)
          idxs(j)  = itemp
          temp     = heap(i)
          heap(i)  = heap(j)
          heap(j)  = temp 
          i        = j 
        else
          exit
        end if
      end do

    case default
      write(0,*) 'Invalid direction in heap ',dir
    end select

    return
  end subroutine psi_dcomplex_idx_heap_get_first



end module psb_sort_mod