!   
!                Parallel Sparse BLAS  version 3.5
!      (C) Copyright 2006-2018
!        Salvatore Filippone    
!        Alfredo Buttari      
!   
!    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.
!   
!    
module psi_d_collective_mod
  use psi_penv_mod

  interface psb_max
    module procedure psb_dmaxs, psb_dmaxv, psb_dmaxm, &
         & psb_dmaxs_ec, psb_dmaxv_ec, psb_dmaxm_ec
  end interface

  interface psb_min
    module procedure psb_dmins, psb_dminv, psb_dminm, &
         & psb_dmins_ec, psb_dminv_ec, psb_dminm_ec
  end interface psb_min

  interface psb_nrm2
    module procedure psb_d_nrm2s, psb_d_nrm2v, &
         & psb_d_nrm2s_ec, psb_d_nrm2v_ec
  end interface psb_nrm2

  interface psb_sum
    module procedure psb_dsums, psb_dsumv, psb_dsumm, &
         & psb_dsums_ec, psb_dsumv_ec, psb_dsumm_ec
  end interface

  interface psb_amx
    module procedure psb_damxs, psb_damxv, psb_damxm, &
         & psb_damxs_ec, psb_damxv_ec, psb_damxm_ec
  end interface

  interface psb_amn
    module procedure psb_damns, psb_damnv, psb_damnm, &
         & psb_damns_ec, psb_damnv_ec, psb_damnm_ec
  end interface


  interface psb_bcast
    module procedure psb_dbcasts, psb_dbcastv, psb_dbcastm, &
         & psb_dbcasts_ec, psb_dbcastv_ec, psb_dbcastm_ec
  end interface psb_bcast

  interface psb_scan_sum
    module procedure psb_dscan_sums, psb_dscan_sumv
  end interface psb_scan_sum

  interface psb_exscan_sum
    module procedure psb_dexscan_sums, psb_dexscan_sumv
  end interface psb_exscan_sum




contains 

  ! !!!!!!!!!!!!!!!!!!!!!!
  !
  ! Reduction operations
  !
  ! !!!!!!!!!!!!!!!!!!!!!!


  ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !
  !  MAX
  !
  ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  subroutine psb_dmaxs(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_max,ictxt,info)
      dat = dat_
    else
      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_max,root_,ictxt,info)
      if (iam == root_) dat = dat_
    endif
#endif    
  end subroutine psb_dmaxs

  subroutine psb_dmaxv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_) &
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_max,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_max,root_,ictxt,info)
      else
        call psb_realloc(1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_max,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_dmaxv

  subroutine psb_dmaxm(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:,:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)

    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_)&
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_max,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_max,root_,ictxt,info)
      else
        call psb_realloc(1,1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_max,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_dmaxm


  subroutine psb_dmaxs_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_max(ictxt_,dat,root_)
    else
      call psb_max(ictxt_,dat)
    end if
  end subroutine psb_dmaxs_ec

  subroutine psb_dmaxv_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_max(ictxt_,dat,root_)
    else
      call psb_max(ictxt_,dat)
    end if
  end subroutine psb_dmaxv_ec

  subroutine psb_dmaxm_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_max(ictxt_,dat,root_)
    else
      call psb_max(ictxt_,dat)
    end if
  end subroutine psb_dmaxm_ec


  !
  ! MIN: Minimum Value
  !


  subroutine psb_dmins(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_min,ictxt,info)
      dat = dat_
    else
      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_min,root_,ictxt,info)
      if (iam == root_) dat = dat_
    endif
#endif    
  end subroutine psb_dmins

  subroutine psb_dminv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_) &
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_min,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_min,root_,ictxt,info)
      else
        call psb_realloc(1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_min,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_dminv

  subroutine psb_dminm(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:,:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)

    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_)&
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_min,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_min,root_,ictxt,info)
      else
        call psb_realloc(1,1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_min,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_dminm


  subroutine psb_dmins_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_min(ictxt_,dat,root_)
    else
      call psb_min(ictxt_,dat)
    end if
  end subroutine psb_dmins_ec

  subroutine psb_dminv_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_min(ictxt_,dat,root_)
    else
      call psb_min(ictxt_,dat)
    end if
  end subroutine psb_dminv_ec

  subroutine psb_dminm_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_min(ictxt_,dat,root_)
    else
      call psb_min(ictxt_,dat)
    end if
  end subroutine psb_dminm_ec



  ! !!!!!!!!!!!!
  !
  ! Norm 2, only for reals
  !
  ! !!!!!!!!!!!!
  subroutine psb_d_nrm2s(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)            :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional  :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_dnrm2_op,ictxt,info)
      dat = dat_
    else
      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_dnrm2_op,root_,ictxt,info)
      if (iam == root_) dat = dat_
    endif
#endif    
  end subroutine psb_d_nrm2s

  subroutine psb_d_nrm2v(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_) &
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,&
           & mpi_dnrm2_op,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,&
             & mpi_dnrm2_op,root_,ictxt,info)
      else
        call psb_realloc(1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,&
             & mpi_dnrm2_op,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_d_nrm2v

  subroutine psb_d_nrm2s_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)            :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional  :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_nrm2(ictxt_,dat,root_)
    else
      call psb_nrm2(ictxt_,dat)
    end if
  end subroutine psb_d_nrm2s_ec
  
  subroutine psb_d_nrm2v_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_nrm2(ictxt_,dat,root_)
    else
      call psb_nrm2(ictxt_,dat)
    end if
  end subroutine psb_d_nrm2v_ec


  !
  ! SUM
  !

  subroutine psb_dsums(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_sum,ictxt,info)
      dat = dat_
    else
      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_sum,root_,ictxt,info)
      if (iam == root_) dat = dat_
    endif
#endif    
  end subroutine psb_dsums

  subroutine psb_dsumv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_) &
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,ictxt,info)
      else
        call psb_realloc(1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_dsumv

  subroutine psb_dsumm(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:,:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)

    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_)&
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,ictxt,info)
      else
        call psb_realloc(1,1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_sum,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_dsumm

  subroutine psb_dsums_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_sum(ictxt_,dat,root_)
    else
      call psb_sum(ictxt_,dat)
    end if
  end subroutine psb_dsums_ec

  subroutine psb_dsumv_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_sum(ictxt_,dat,root_)
    else
      call psb_sum(ictxt_,dat)
    end if
  end subroutine psb_dsumv_ec
  
  subroutine psb_dsumm_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_sum(ictxt_,dat,root_)
    else
      call psb_sum(ictxt_,dat)
    end if
  end subroutine psb_dsumm_ec


  !
  ! AMX: Maximum Absolute Value
  !
  
  subroutine psb_damxs(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_damx_op,ictxt,info)
      dat = dat_
    else
      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_damx_op,root_,ictxt,info)
      if (iam == root_) dat = dat_
    endif
#endif    
  end subroutine psb_damxs

  subroutine psb_damxv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_) &
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damx_op,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damx_op,root_,ictxt,info)
      else
        call psb_realloc(1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_damx_op,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_damxv

  subroutine psb_damxm(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:,:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)

    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_)&
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damx_op,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damx_op,root_,ictxt,info)
      else
        call psb_realloc(1,1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_damx_op,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_damxm


  subroutine psb_damxs_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_amx(ictxt_,dat,root_)
    else
      call psb_amx(ictxt_,dat)
    end if
  end subroutine psb_damxs_ec

  subroutine psb_damxv_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_amx(ictxt_,dat,root_)
    else
      call psb_amx(ictxt_,dat)
    end if
  end subroutine psb_damxv_ec

  subroutine psb_damxm_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_amx(ictxt_,dat,root_)
    else
      call psb_amx(ictxt_,dat)
    end if
  end subroutine psb_damxm_ec


  !
  ! AMN: Minimum Absolute Value
  !
  
  subroutine psb_damns(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call mpi_allreduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_damn_op,ictxt,info)
      dat = dat_
    else
      call mpi_reduce(dat,dat_,1,psb_mpi_r_dpk_,mpi_damn_op,root_,ictxt,info)
      if (iam == root_) dat = dat_
    endif
#endif    
  end subroutine psb_damns

  subroutine psb_damnv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_) &
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damn_op,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damn_op,root_,ictxt,info)
      else
        call psb_realloc(1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_damn_op,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_damnv

  subroutine psb_damnm(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:,:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)

    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = -1
    endif
    if (root_ == -1) then 
      call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
      dat_ = dat
      if (iinfo == psb_success_)&
           & call mpi_allreduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damn_op,ictxt,info)
    else
      if (iam == root_) then 
        call psb_realloc(size(dat,1),size(dat,2),dat_,iinfo)
        dat_ = dat
        call mpi_reduce(dat_,dat,size(dat),psb_mpi_r_dpk_,mpi_damn_op,root_,ictxt,info)
      else
        call psb_realloc(1,1,dat_,iinfo)
        call mpi_reduce(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_damn_op,root_,ictxt,info)
      end if
    endif
#endif    
  end subroutine psb_damnm


  subroutine psb_damns_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_amn(ictxt_,dat,root_)
    else
      call psb_amn(ictxt_,dat)
    end if
  end subroutine psb_damns_ec

  subroutine psb_damnv_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_amn(ictxt_,dat,root_)
    else
      call psb_amn(ictxt_,dat)
    end if
  end subroutine psb_damnv_ec

  subroutine psb_damnm_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_amn(ictxt_,dat,root_)
    else
      call psb_amn(ictxt_,dat)
    end if
  end subroutine psb_damnm_ec


  !
  ! BCAST Broadcast
  !
  
  subroutine psb_dbcasts(ictxt,dat,root)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_

    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = psb_root_
    endif
    call mpi_bcast(dat,1,psb_mpi_r_dpk_,root_,ictxt,info)

#endif    
  end subroutine psb_dbcasts

  subroutine psb_dbcastv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = psb_root_
    endif
    
    call mpi_bcast(dat,size(dat),psb_mpi_r_dpk_,root_,ictxt,info)
#endif    
  end subroutine psb_dbcastv

  subroutine psb_dbcastm(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_

    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)

    call psb_info(ictxt,iam,np)

    if (present(root)) then 
      root_ = root
    else
      root_ = psb_root_
    endif

    call mpi_bcast(dat,size(dat),psb_mpi_r_dpk_,root_,ictxt,info)
#endif    
  end subroutine psb_dbcastm


  subroutine psb_dbcasts_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_bcast(ictxt_,dat,root_)
    else
      call psb_bcast(ictxt_,dat)
    end if
  end subroutine psb_dbcasts_ec

  subroutine psb_dbcastv_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_bcast(ictxt_,dat,root_)
    else
      call psb_bcast(ictxt_,dat)
    end if
  end subroutine psb_dbcastv_ec

  subroutine psb_dbcastm_ec(ictxt,dat,root)
    implicit none 
    integer(psb_epk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:,:)
    integer(psb_epk_), intent(in), optional    :: root
    integer(psb_mpk_) :: ictxt_, root_

    ictxt_ = ictxt
    if (present(root)) then 
      root_ = root
      call psb_bcast(ictxt_,dat,root_)
    else
      call psb_bcast(ictxt_,dat)
    end if
  end subroutine psb_dbcastm_ec


  ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
  !
  !  SCAN
  !
  ! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

  subroutine psb_dscan_sums(ictxt,dat)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)
    call mpi_scan(dat,dat_,1,psb_mpi_r_dpk_,mpi_sum,ictxt,info)
    dat = dat_
#endif    
  end subroutine psb_dscan_sums


  subroutine psb_dexscan_sums(ictxt,dat)
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat
    real(psb_dpk_) :: dat_
    integer(psb_mpk_) :: iam, np, info
    integer(psb_ipk_) :: iinfo


#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)
    call mpi_exscan(dat,dat_,1,psb_mpi_r_dpk_,mpi_sum,ictxt,info)
    dat = dat_
#else
    dat = dzero
#endif    
  end subroutine psb_dexscan_sums

  subroutine psb_dscan_sumv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)
    call psb_realloc(size(dat),dat_,iinfo)
    dat_ = dat
    if (iinfo == psb_success_) &
         & call mpi_scan(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_sum,ictxt,info)
#endif
  end subroutine psb_dscan_sumv

  subroutine psb_dexscan_sumv(ictxt,dat,root)
    use psb_realloc_mod
#ifdef MPI_MOD
    use mpi
#endif
    implicit none 
#ifdef MPI_H
    include 'mpif.h'
#endif
    integer(psb_mpk_), intent(in)              :: ictxt
    real(psb_dpk_), intent(inout)  :: dat(:)
    integer(psb_mpk_), intent(in), optional    :: root
    integer(psb_mpk_) :: root_
    real(psb_dpk_), allocatable :: dat_(:)
    integer(psb_mpk_) :: iam, np,  info
    integer(psb_ipk_) :: iinfo

#if !defined(SERIAL_MPI)
    call psb_info(ictxt,iam,np)
    call psb_realloc(size(dat),dat_,iinfo)
    dat_ = dat
    if (iinfo == psb_success_) &
         & call mpi_exscan(dat,dat_,size(dat),psb_mpi_r_dpk_,mpi_sum,ictxt,info)
#else
    dat = dzero
#endif
  end subroutine psb_dexscan_sumv
  
end module psi_d_collective_mod