!!$
!!$ Parallel Sparse BLAS version 3.0
!!$ (C) Copyright 2006, 2007, 2008, 2009, 2010
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$ Alfredo Buttari CNRS-IRIT, Toulouse
!!$
!!$ 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.
!!$
!!$
!!$ CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
!!$ C C
!!$ C References: C
!!$ C [1] Duff, I., Marrone, M., Radicati, G., and Vittoli, C. C
!!$ C Level 3 basic linear algebra subprograms for sparse C
!!$ C matrices: a user level interface C
!!$ C ACM Trans. Math. Softw., 23(3), 379-401, 1997. C
!!$ C C
!!$ C C
!!$ C [2] S. Filippone, M. Colajanni C
!!$ C PSBLAS: A library for parallel linear algebra C
!!$ C computation on sparse matrices C
!!$ C ACM Trans. on Math. Softw., 26(4), 527-550, Dec. 2000. C
!!$ C C
!!$ C [3] M. Arioli, I. Duff, M. Ruiz C
!!$ C Stopping criteria for iterative solvers C
!!$ C SIAM J. Matrix Anal. Appl., Vol. 13, pp. 138-144, 1992 C
!!$ C C
!!$ C C
!!$ C [4] R. Barrett et al C
!!$ C Templates for the solution of linear systems C
!!$ C SIAM, 1993
!!$ C C
!!$ C C
!!$ CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
! File: psb_dcgstab.f90
!
! Subroutine: psb_dcgstab
! This subroutine implements the BiCG Stabilized method.
!
!
! Arguments:
!
! a - type(psb_dspmat_type) Input: sparse matrix containing A.
! prec - class(psb_dprec_type) Input: preconditioner
! b - real,dimension(:) Input: vector containing the
! right hand side B
! x - real,dimension(:) Input/Output: vector containing the
! initial guess and final solution X.
! eps - real Input: Stopping tolerance; the iteration is
! stopped when the error estimate |err| <= eps
! desc_a - type(psb_desc_type). Input: The communication descriptor.
! info - integer. Output: Return code
!
! itmax - integer(optional) Input: maximum number of iterations to be
! performed.
! iter - integer(optional) Output: how many iterations have been
! performed.
! err - real (optional) Output: error estimate on exit. If the
! denominator of the estimate is exactly
! 0, it is changed into 1.
! itrace - integer(optional) Input: print an informational message
! with the error estimate every itrace
! iterations
! istop - integer(optional) Input: stopping criterion, or how
! to estimate the error.
! 1: err = |r|/(|a||x|+|b|); here the iteration is
! stopped when |r| <= eps * (|a||x|+|b|)
! 2: err = |r|/|b|; here the iteration is
! stopped when |r| <= eps * |b|
! where r is the (preconditioned, recursive
! estimate of) residual.
!
!
!
!!$Subroutine psb_dcgstab(a,prec,b,x,eps,desc_a,info,itmax,iter,err,itrace,istop)
!!$ use psb_base_mod
!!$ use psb_prec_mod
!!$ use psb_d_inner_krylov_mod
!!$ use psb_krylov_mod
!!$ implicit none
!!$
!!$ type(psb_dspmat_type), intent(in) :: a
!!$ class(psb_dprec_type), Intent(in) :: prec
!!$ Type(psb_desc_type), Intent(in) :: desc_a
!!$ Real(psb_dpk_), Intent(in) :: b(:)
!!$ Real(psb_dpk_), Intent(inout) :: x(:)
!!$ Real(psb_dpk_), Intent(in) :: eps
!!$ integer(psb_ipk_), intent(out) :: info
!!$ integer(psb_ipk_), Optional, Intent(in) :: itmax, itrace, istop
!!$ integer(psb_ipk_), Optional, Intent(out) :: iter
!!$ Real(psb_dpk_), Optional, Intent(out) :: err
!!$! !$ Local data
!!$ Real(psb_dpk_), allocatable, target :: aux(:),wwrk(:,:)
!!$ Real(psb_dpk_), Pointer :: q(:),&
!!$ & r(:), p(:), v(:), s(:), t(:), z(:), f(:)
!!$ integer(psb_ipk_) :: itmax_, naux, mglob, it,itrace_,&
!!$ & np,me, n_row, n_col
!!$ integer(psb_ipk_) :: debug_level, debug_unit
!!$ Logical, Parameter :: exchange=.True., noexchange=.False., debug1 = .False.
!!$ integer(psb_ipk_), Parameter :: irmax = 8
!!$ integer(psb_ipk_) :: itx, isvch, ictxt, err_act, i
!!$ integer(psb_ipk_) :: istop_
!!$ Real(psb_dpk_) :: alpha, beta, rho, rho_old, sigma, omega, tau
!!$ type(psb_itconv_type) :: stopdat
!!$
!!$#ifdef MPE_KRYLOV
!!$ include "mpe_logf.h"
!!$ Integer istpb, istpe, ifctb, ifcte, imerr, irank, icomm,immb,imme
!!$#endif
!!$ character(len=20) :: name
!!$ character(len=*), parameter :: methdname='BiCGStab'
!!$
!!$ info = psb_success_
!!$ name = 'psb_dcgstab'
!!$ call psb_erractionsave(err_act)
!!$ debug_unit = psb_get_debug_unit()
!!$ debug_level = psb_get_debug_level()
!!$ ictxt = desc_a%get_context()
!!$ call psb_info(ictxt, me, np)
!!$ if (debug_level >= psb_debug_ext_)&
!!$ & write(debug_unit,*) me,' ',trim(name),': from psb_info',np
!!$
!!$#ifdef MPE_KRYLOV
!!$! !$ call psb_get_mpicomm(ictxt,icomm)
!!$! !$ call psb_get_rank(irank,icomm,me)
!!$ imerr = MPE_Log_get_state_eventIDs(istpb,istpe)
!!$ imerr = MPE_Log_get_state_eventIDs(ifctb,ifcte)
!!$ imerr = MPE_Log_get_state_eventIDs(immb,imme)
!!$
!!$ if (me == 0) then
!!$ info = mpe_describe_state(istpb,istpe,"Solver","WhiteSmoke")
!!$ info = mpe_describe_state(ifctb,ifcte,"PREC","SteelBlue")
!!$ info = mpe_describe_state(immb,imme,"SPMM","DarkOrange")
!!$ endif
!!$ call psb_barrier(ictxt)
!!$ call mpi_Pcontrol(1,info)
!!$#endif
!!$
!!$ mglob = desc_a%get_global_rows()
!!$ n_row = desc_a%get_local_rows()
!!$ n_col = desc_a%get_local_cols()
!!$
!!$ If (Present(istop)) Then
!!$ istop_ = istop
!!$ Else
!!$ istop_ = 2
!!$ Endif
!!$ !
!!$ ! ISTOP_ = 1: Normwise backward error, infinity norm
!!$ ! ISTOP_ = 2: ||r||/||b|| norm 2
!!$ !
!!$
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( istpb, 0, "st CGSTAB" )
!!$#endif
!!$
!!$
!!$ call psb_chkvect(mglob,1,size(x,1),1,1,desc_a,info)
!!$ if(info /= psb_success_) then
!!$ info=psb_err_from_subroutine_
!!$ call psb_errpush(info,name,a_err='psb_chkvect on X')
!!$ goto 9999
!!$ end if
!!$ call psb_chkvect(mglob,1,size(b,1),1,1,desc_a,info)
!!$ if(info /= psb_success_) then
!!$ info=psb_err_from_subroutine_
!!$ call psb_errpush(info,name,a_err='psb_chkvect on B')
!!$ goto 9999
!!$ end if
!!$
!!$ naux=6*n_col
!!$ allocate(aux(naux),stat=info)
!!$ if (info == psb_success_) call psb_geall(wwrk,desc_a,info,n=8)
!!$ if (info == psb_success_) call psb_geasb(wwrk,desc_a,info)
!!$
!!$ if (info /= psb_success_) then
!!$ info=psb_err_from_subroutine_non_
!!$ call psb_errpush(info,name)
!!$ goto 9999
!!$ End If
!!$
!!$ Q => WWRK(:,1)
!!$ R => WWRK(:,2)
!!$ P => WWRK(:,3)
!!$ V => WWRK(:,4)
!!$ F => WWRK(:,5)
!!$ S => WWRK(:,6)
!!$ T => WWRK(:,7)
!!$ Z => WWRK(:,8)
!!$
!!$ If (Present(itmax)) Then
!!$ itmax_ = itmax
!!$ Else
!!$ itmax_ = 1000
!!$ Endif
!!$
!!$ If (Present(itrace)) Then
!!$ itrace_ = itrace
!!$ Else
!!$ itrace_ = 0
!!$ End If
!!$
!!$ ! Ensure global coherence for convergence checks.
!!$ call psb_set_coher(ictxt,isvch)
!!$
!!$ itx = 0
!!$ call psb_init_conv(methdname,istop_,itrace_,itmax_,a,b,eps,desc_a,stopdat,info)
!!$ if (psb_errstatus_fatal()) Then
!!$ call psb_errpush(psb_err_from_subroutine_non_,name)
!!$ goto 9999
!!$ End If
!!$
!!$ restart: Do
!!$
!!$ if (itx >= itmax_) exit restart
!!$
!!$ it = 0
!!$ call psb_geaxpby(done,b,dzero,r,desc_a,info)
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( immb, 0, "st SPMM" )
!!$#endif
!!$ if (info == psb_success_) call psb_spmm(-done,a,x,done,r,desc_a,info,work=aux)
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( imme, 0, "ed SPMM" )
!!$#endif
!!$ if (info == psb_success_) call psb_geaxpby(done,r,dzero,q,desc_a,info)
!!$ if (psb_errstatus_fatal()) then
!!$ info=psb_err_from_subroutine_
!!$ call psb_errpush(info,name,a_err='Init residual')
!!$ goto 9999
!!$ end if
!!$
!!$ ! Perhaps we already satisfy the convergence criterion...
!!$ if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
!!$ if (psb_errstatus_fatal()) Then
!!$ call psb_errpush(psb_err_from_subroutine_non_,name)
!!$ goto 9999
!!$ End If
!!$
!!$ rho = dzero
!!$
!!$ iteration: Do
!!$ it = it + 1
!!$ itx = itx + 1
!!$
!!$ if (debug_level >= psb_debug_ext_)&
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Iteration: ',itx
!!$
!!$ rho_old = rho
!!$ rho = psb_gedot(q,r,desc_a,info)
!!$
!!$ if (debug_level >= psb_debug_ext_)&
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Rho: ',rho
!!$
!!$ if (rho == dzero) then
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Iteration breakdown R',rho
!!$ exit iteration
!!$ endif
!!$
!!$ if (it == 1) then
!!$ call psb_geaxpby(done,r,dzero,p,desc_a,info)
!!$ else
!!$ beta = (rho/rho_old)*(alpha/omega)
!!$ call psb_geaxpby(-omega,v,done,p,desc_a,info)
!!$ call psb_geaxpby(done,r,beta,p,desc_a,info)
!!$ End If
!!$
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( ifctb, 0, "st PREC" )
!!$#endif
!!$ if (debug_level >= psb_debug_inner_) write(0,*) 'P: ',p
!!$ call prec%apply(p,f,desc_a,info,work=aux)
!!$ if (debug_level >= psb_debug_inner_) write(0,*) 'F: ',f
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( ifcte, 0, "ed PREC" )
!!$ imerr = MPE_Log_event( immb, 0, "st SPMM" )
!!$#endif
!!$ call psb_spmm(done,a,f,dzero,v,desc_a,info,&
!!$ & work=aux)
!!$ if (debug_level >= psb_debug_inner_) write(0,*) 'Q: ',q
!!$ if (debug_level >= psb_debug_inner_) write(0,*) 'V: ',v
!!$
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( imme, 0, "ed SPMM" )
!!$#endif
!!$
!!$ sigma = psb_gedot(q,v,desc_a,info)
!!$
!!$ if (debug_level >= psb_debug_ext_)&
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Sigma: ',sigma
!!$ if (sigma == dzero) then
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Iteration breakdown S1', sigma
!!$ exit iteration
!!$ endif
!!$
!!$ alpha = rho/sigma
!!$ call psb_geaxpby(done,r,dzero,s,desc_a,info)
!!$ if (info == psb_success_) call psb_geaxpby(-alpha,v,done,s,desc_a,info)
!!$ if (debug_level >= psb_debug_ext_)&
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' alpha: ',alpha
!!$
!!$ if(psb_errstatus_fatal()) then
!!$ call psb_errpush(psb_err_from_subroutine_,name,a_err='psb_geaxpby')
!!$ goto 9999
!!$ end if
!!$
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( ifctb, 0, "st PREC" )
!!$#endif
!!$ call prec%apply(s,z,desc_a,info,work=aux)
!!$
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( ifcte, 0, "ed PREC" )
!!$ imerr = MPE_Log_event( immb, 0, "st SPMM" )
!!$#endif
!!$ if (info == psb_success_) Call psb_spmm(done,a,z,dzero,t,desc_a,info,&
!!$ & work=aux)
!!$
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( imme, 0, "ed SPMM" )
!!$#endif
!!$ if(psb_errstatus_fatal()) then
!!$ call psb_errpush(psb_err_from_subroutine_,name,a_err='precaply/spmm')
!!$ goto 9999
!!$ end if
!!$
!!$ sigma = psb_gedot(t,t,desc_a,info)
!!$ if (sigma == dzero) then
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Iteration breakdown S2', sigma
!!$ exit iteration
!!$ endif
!!$
!!$ tau = psb_gedot(t,s,desc_a,info)
!!$ omega = tau/sigma
!!$
!!$
!!$ if (debug_level >= psb_debug_ext_)&
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' sigma, tau, omega: ',sigma, tau, omega
!!$ if (omega == dzero) then
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' Iteration breakdown O',omega
!!$ exit iteration
!!$ endif
!!$
!!$ call psb_geaxpby(alpha,f,done,x,desc_a,info)
!!$ if (info == psb_success_) call psb_geaxpby(omega,z,done,x,desc_a,info)
!!$ if (info == psb_success_) call psb_geaxpby(done,s,dzero,r,desc_a,info)
!!$ if (info == psb_success_) call psb_geaxpby(-omega,t,done,r,desc_a,info)
!!$ if (psb_errstatus_fatal()) Then
!!$ call psb_errpush(psb_err_from_subroutine_,name,a_err='X/R update ')
!!$ goto 9999
!!$ End If
!!$
!!$ if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
!!$ if (psb_errstatus_fatal()) Then
!!$ call psb_errpush(psb_err_from_subroutine_non_,name)
!!$ goto 9999
!!$ End If
!!$
!!$ end do iteration
!!$ end do restart
!!$
!!$ call psb_end_conv(methdname,itx,desc_a,stopdat,info,err,iter)
!!$
!!$ deallocate(aux,stat=info)
!!$ call psb_gefree(wwrk,desc_a,info)
!!$ if((info /= 0).or.(psb_errstatus_fatal())) then
!!$ call psb_errpush(info,name)
!!$ goto 9999
!!$ end if
!!$#ifdef MPE_KRYLOV
!!$ imerr = MPE_Log_event( istpe, 0, "ed CGSTAB" )
!!$ call mpi_Pcontrol(2,info)
!!$ call mpi_Pcontrol(0,info)
!!$#endif
!!$ ! restore external global coherence behaviour
!!$ call psb_restore_coher(ictxt,isvch)
!!$
!!$ 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
!!$
!!$End Subroutine psb_dcgstab
Subroutine psb_dcgstab_vect(a,prec,b,x,eps,desc_a,info,itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
use psb_d_inner_krylov_mod
use psb_krylov_mod
implicit none
type(psb_dspmat_type), intent(in) :: a
class(psb_dprec_type), Intent(inout) :: prec
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_d_vect_type), Intent(inout) :: b
type(psb_d_vect_type), Intent(inout) :: x
Real(psb_dpk_), Intent(in) :: eps
integer(psb_ipk_), intent(out) :: info
integer(psb_ipk_), Optional, Intent(in) :: itmax, itrace, istop
integer(psb_ipk_), Optional, Intent(out) :: iter
Real(psb_dpk_), Optional, Intent(out) :: err
!!$ Local data
Real(psb_dpk_), allocatable, target :: aux(:),wwrk(:,:)
type(psb_d_vect_type) :: q, r, p, v, s, t, z, f
integer(psb_ipk_) :: itmax_, naux, mglob, it,itrace_,&
& np,me, n_row, n_col
integer(psb_ipk_) :: debug_level, debug_unit
Logical, Parameter :: exchange=.True., noexchange=.False., debug1 = .False.
integer(psb_ipk_), Parameter :: irmax = 8
integer(psb_ipk_) :: itx, isvch, ictxt, err_act, i
integer(psb_ipk_) :: istop_
Real(psb_dpk_) :: alpha, beta, rho, rho_old, sigma, omega, tau
type(psb_itconv_type) :: stopdat
real(psb_dpk_), external :: ddot
character(len=20) :: name
character(len=*), parameter :: methdname='BiCGStab'
info = psb_success_
name = 'psb_dcgstab'
call psb_erractionsave(err_act)
debug_unit = psb_get_debug_unit()
debug_level = psb_get_debug_level()
ictxt = desc_a%get_context()
call psb_info(ictxt, me, np)
if (debug_level >= psb_debug_ext_)&
& write(debug_unit,*) me,' ',trim(name),': from psb_info',np
if (.not.allocated(x%v)) then
info = psb_err_invalid_vect_state_
call psb_errpush(info,name)
goto 9999
endif
if (.not.allocated(b%v)) then
info = psb_err_invalid_vect_state_
call psb_errpush(info,name)
goto 9999
endif
mglob = desc_a%get_global_rows()
n_row = desc_a%get_local_rows()
n_col = desc_a%get_local_cols()
If (Present(istop)) Then
istop_ = istop
Else
istop_ = 2
Endif
!
! ISTOP_ = 1: Normwise backward error, infinity norm
! ISTOP_ = 2: ||r||/||b|| norm 2
!
!!$ if (.not.same_type_as(x,b)) then
!!$ write(0,*) 'Warning: different dynamic types for X and B '
!!$ end if
call psb_chkvect(mglob,1,x%get_nrows(),1,1,desc_a,info)
if (psb_errstatus_fatal()) then
info=psb_err_from_subroutine_
call psb_errpush(info,name,a_err='psb_chkvect on X')
goto 9999
end if
call psb_chkvect(mglob,1,b%get_nrows(),1,1,desc_a,info)
if (psb_errstatus_fatal()) then
info=psb_err_from_subroutine_
call psb_errpush(info,name,a_err='psb_chkvect on B')
goto 9999
end if
naux=6*n_col
if (info == psb_success_) allocate(aux(naux),stat=info)
if (info /= psb_success_) then
info=psb_err_alloc_dealloc_
call psb_errpush(info,name)
goto 9999
End If
call psb_geasb(q,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(r,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(p,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(v,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(s,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(t,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(z,desc_a,info,mold=x%v,scratch=.true.)
call psb_geasb(f,desc_a,info,mold=x%v,scratch=.true.)
if (psb_errstatus_fatal()) then
info=psb_err_from_subroutine_non_
call psb_errpush(info,name)
goto 9999
End If
If (Present(itmax)) Then
itmax_ = itmax
Else
itmax_ = 1000
Endif
If (Present(itrace)) Then
itrace_ = itrace
Else
itrace_ = 0
End If
! Ensure global coherence for convergence checks.
call psb_set_coher(ictxt,isvch)
itx = 0
call psb_init_conv(methdname,istop_,itrace_,itmax_,a,b,eps,desc_a,stopdat,info)
if (psb_errstatus_fatal()) Then
call psb_errpush(psb_err_from_subroutine_non_,name)
goto 9999
End If
restart: Do
if (itx >= itmax_) exit restart
it = 0
call psb_geaxpby(done,b,dzero,r,desc_a,info)
call psb_spmm(-done,a,x,done,r,desc_a,info,work=aux)
call psb_geaxpby(done,r,dzero,q,desc_a,info)
! Perhaps we already satisfy the convergence criterion...
if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
if (psb_errstatus_fatal()) then
info=psb_err_from_subroutine_
call psb_errpush(info,name,a_err='Init residual chk')
goto 9999
end if
rho = dzero
iteration: Do
it = it + 1
itx = itx + 1
if (debug_level >= psb_debug_ext_)&
& write(debug_unit,*) me,' ',trim(name),&
& ' Iteration: ',itx
rho_old = rho
rho = psb_gedot(q,r,desc_a,info)
if (debug_level >= psb_debug_ext_) then
call q%sync()
call r%sync()
end if
if (debug_level >= psb_debug_ext_)&
& write(debug_unit,*) me,' ',trim(name),&
& ' Rho: ',rho, ddot(n_row,q%v,1,r%v,1)
if (rho == dzero) then
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' Iteration breakdown R',rho
exit iteration
endif
if (it == 1) then
call psb_geaxpby(done,r,dzero,p,desc_a,info)
else
beta = (rho/rho_old)*(alpha/omega)
call psb_geaxpby(-omega,v,done,p,desc_a,info)
call psb_geaxpby(done,r,beta,p,desc_a,info)
End If
call prec%apply(p,f,desc_a,info,work=aux)
call psb_spmm(done,a,f,dzero,v,desc_a,info,&
& work=aux)
sigma = psb_gedot(q,v,desc_a,info)
if (debug_level >= psb_debug_ext_) then
call q%sync()
call v%sync()
end if
if (debug_level >= psb_debug_ext_)&
& write(debug_unit,*) me,' ',trim(name),&
& ' Sigma: ',sigma, ddot(n_row,q%v,1,v%v,1)
if (sigma == dzero) then
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' Iteration breakdown S1', sigma
exit iteration
endif
alpha = rho/sigma
call psb_geaxpby(done,r,dzero,s,desc_a,info)
call psb_geaxpby(-alpha,v,done,s,desc_a,info)
if (debug_level >= psb_debug_ext_)&
& write(debug_unit,*) me,' ',trim(name),&
& ' alpha: ',alpha
if (psb_errstatus_fatal()) then
call psb_errpush(psb_err_from_subroutine_,name,a_err='psb_geaxpby')
goto 9999
end if
call prec%apply(s,z,desc_a,info,work=aux)
Call psb_spmm(done,a,z,dzero,t,desc_a,info,work=aux)
if(psb_errstatus_fatal()) then
call psb_errpush(psb_err_from_subroutine_,name,a_err='precaply/spmm')
goto 9999
end if
sigma = psb_gedot(t,t,desc_a,info)
if (sigma == dzero) then
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' Iteration breakdown S2', sigma
exit iteration
endif
tau = psb_gedot(t,s,desc_a,info)
omega = tau/sigma
if (debug_level >= psb_debug_ext_) then
call t%sync()
call s%sync()
end if
if (debug_level >= psb_debug_ext_)&
& write(debug_unit,*) me,' ',trim(name),&
& ' sigma, tau, omega: ',sigma, tau, omega&
&, ddot(n_row,t%v,1,t%v,1), ddot(n_row,t%v,1,s%v,1)
if (omega == dzero) then
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' Iteration breakdown O',omega
exit iteration
endif
call psb_geaxpby(alpha,f,done,x,desc_a,info)
call psb_geaxpby(omega,z,done,x,desc_a,info)
call psb_geaxpby(done,s,dzero,r,desc_a,info)
call psb_geaxpby(-omega,t,done,r,desc_a,info)
if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
if (psb_errstatus_fatal()) Then
call psb_errpush(psb_err_from_subroutine_,name,a_err='X/R update ')
goto 9999
End If
end do iteration
end do restart
call psb_end_conv(methdname,itx,desc_a,stopdat,info,err,iter)
deallocate(aux,stat=info)
call x%sync()
call psb_gefree(q,desc_a,info)
call psb_gefree(r,desc_a,info)
call psb_gefree(p,desc_a,info)
call psb_gefree(v,desc_a,info)
call psb_gefree(s,desc_a,info)
call psb_gefree(t,desc_a,info)
call psb_gefree(z,desc_a,info)
call psb_gefree(f,desc_a,info)
if(psb_errstatus_fatal()) then
call psb_errpush(info,name)
goto 9999
end if
! restore external global coherence behaviour
call psb_restore_coher(ictxt,isvch)
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 Subroutine psb_dcgstab_vect