psblas3/base/serial/psb_zspclip.f90

!!$ 
!!$              Parallel Sparse BLAS  v2.0
!!$    (C) Copyright 2006 Salvatore Filippone    University of Rome Tor Vergata
!!$                       Alfredo Buttari        University of Rome Tor Vergata
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! File:  psb_zspclip.f90 
! Subroutine: psb_zspclip
!    Creates a "clipped" copy of input matrix A. Output is always in COO. 
! Parameters:

!*****************************************************************************
!*                                                                           *
!*****************************************************************************
subroutine psb_zspclip(a,b,info,imin,imax,jmin,jmax,rscale,cscale)
  use psb_spmat_type
  use psb_string_mod
  use psb_serial_mod, psb_protect_name => psb_zspclip
  implicit none 
  type(psb_zspmat_type), intent(in)  :: a
  type(psb_zspmat_type), intent(out) :: b
  integer, intent(out)               :: info
  integer, intent(in), optional      :: imin,imax,jmin,jmax
  logical, intent(in), optional      :: rscale,cscale

  integer               :: lrw_, ierr(5), err_act
  type(psb_zspmat_type) :: tmp
  character(len=20)     :: name, ch_err
  integer      :: imin_,imax_,jmin_,jmax_
  logical      :: rscale_,cscale_
  integer      :: sizeb, nzb, mb, kb, ifst, ilst, nrt, nzt, i, j
  integer, parameter :: irbk=40, inzr=16 
  
  name='psb_zsp_clip'
  info  = 0
  call psb_erractionsave(err_act)
  call psb_set_erraction(0)  

  call psb_nullify_sp(b)
  call psb_sp_all(tmp,inzr*irbk,info)
  

  if (present(imin)) then 
    imin_ = imin
  else
    imin_ = 1
  endif
  if (present(imax)) then 
    imax_ = imax
  else
    imax_ = a%m
  endif
  if (present(jmin)) then 
    jmin_ = jmin
  else
    jmin_ = 1
  endif
  if (present(jmax)) then 
    jmax_ = jmax
  else
    jmax_ = a%k
  endif
  if (present(rscale)) then 
    rscale_ = rscale
  else
    rscale_ = .true.
  endif
  if (present(cscale)) then 
    cscale_ = cscale
  else
    cscale_ = .true.
  endif
  
  if (rscale_) then 
    mb = imax_ - imin_ +1
  else 
    mb = a%m  ! Should this be imax_ ?? 
  endif
  if (cscale_) then 
    kb = jmax_ - jmin_ +1
  else 
    kb = a%k  ! Should this be jmax_ ?? 
  endif


  sizeb = psb_sp_get_nnzeros(a)
  call psb_sp_all(mb,kb,b,sizeb,info)
  b%fida='COO'
  nzb = 0 
  do i=imin_, imax_, irbk
    nrt = min(irbk,imax_-i+1)
    ifst = i
    ilst = ifst + nrt - 1
    call psb_sp_getblk(ifst,a,tmp,info,lrw=ilst)
    nzt = psb_sp_get_nnzeros(tmp)
    do j=1, nzt 
      if ((jmin_ <= tmp%ia2(j)).and.(tmp%ia2(j) <= jmax_)) then 
        nzb         = nzb + 1
        b%aspk(nzb) = tmp%aspk(j) 
        b%ia1(nzb)  = tmp%ia1(j) 
        b%ia2(nzb)  = tmp%ia2(j) 
      end if
    end do
  end do
  b%infoa(psb_nnz_) = nzb 

  if (rscale_) then 
    do i=1, nzb
      b%ia1(i) = b%ia1(i) - imin_ + 1
    end do
  end if
  if (cscale_) then 
    do i=1, nzb
      b%ia2(i) = b%ia2(i) - jmin_ + 1
    end do
  end if
  call psb_fixcoo(b,info) 
  call psb_sp_trim(b,info)
  call psb_sp_free(tmp,info)

  call psb_erractionrestore(err_act)
  return

9999 continue
  call psb_erractionrestore(err_act)
  if (err_act.eq.psb_act_abort_) then
    call psb_error()
    return
  end if
  return

end subroutine psb_zspclip