!!$ 
!!$              Parallel Sparse BLAS  version 3.0
!!$    (C) Copyright 2006, 2007, 2008, 2009, 2010, 2012
!!$                       Salvatore Filippone    University of Rome Tor Vergata
!!$                       Alfredo Buttari        CNRS-IRIT, Toulouse
!!$ 
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!!$  modification, are permitted provided that the following conditions
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!!$ 
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!!$  
! File: psb_snrm1.f90
!
! Function: psb_snrm1
!    Forms the  norm1 of a sparse matrix,       
!
!    norm1 := max_j(sum(abs(A(:,j))))                                                 
!
! Arguments:
!    a      -  type(psb_sspmat_type).   The sparse matrix containing A.
!    desc_a -  type(psb_desc_type).     The communication descriptor.
!    info   -  integer.                   Return code
!
function psb_sspnrm1(a,desc_a,info)  result(res)
  use psb_base_mod, psb_protect_name => psb_sspnrm1
  implicit none

  type(psb_sspmat_type), intent(in) :: a
  integer(psb_ipk_), intent(out)      :: info
  type(psb_desc_type), intent(in)     :: desc_a
  real(psb_spk_)                      :: res

  ! locals
  integer(psb_ipk_) :: ictxt, np, me, nr,nc,&
       & err_act, n, iia, jja, ia, ja, mdim, ndim, m
  character(len=20)      :: name, ch_err
  real(psb_spk_), allocatable :: v(:)

  name='psb_sspnrm1'
  if (psb_errstatus_fatal()) return 
  info=psb_success_
  call psb_erractionsave(err_act)

  ictxt=desc_a%get_context()

  call psb_info(ictxt, me, np)
  if (np == -1) then
    info = psb_err_context_error_
    call psb_errpush(info,name)
    goto 9999
  endif

  ia = 1
  ja = 1
  m = desc_a%get_global_rows()
  n = desc_a%get_global_cols()
  nr = desc_a%get_local_rows()
  nc = desc_a%get_local_cols()

  call psb_chkmat(m,n,ia,ja,desc_a,info,iia,jja)
  if(info /= psb_success_) then
    info=psb_err_from_subroutine_
    ch_err='psb_chkmat'
    call psb_errpush(info,name,a_err=ch_err)
    goto 9999
  end if

  if ((iia /= 1).or.(jja /= 1)) then
    info=psb_err_ix_n1_iy_n1_unsupported_
    call psb_errpush(info,name)
    goto 9999
  end if

  call psb_geall(v,desc_a,info)
  if(info == psb_success_) then 
    v = szero
    call psb_geasb(v,desc_a,info)
  end if
  if(info /= psb_success_) then
    info=psb_err_from_subroutine_
    ch_err='geall/asb'
    call psb_errpush(info,name,a_err=ch_err)
    goto 9999
  end if
  
  if ((m /= 0).and.(n /= 0)) then
    call a%aclsum(v,info)
    if (info == psb_success_) call psb_halo(v,desc_a,info,tran='T')
    if(info /= psb_success_) then
      info=psb_err_from_subroutine_
      ch_err='psb_halo'
      call psb_errpush(info,name,a_err=ch_err)
      goto 9999
    end if
    res = maxval(v(1:nr))
  else
    res = szero 
  end if
  ! compute global max
  call psb_amx(ictxt, res)

  call psb_erractionrestore(err_act)
  return  

9999 continue
  call psb_erractionrestore(err_act)

  if (err_act == psb_act_abort_) then
    call psb_error(ictxt)
    return
  end if
  return
end function psb_sspnrm1