!!$
!!$ 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 C
!!$ C [5] G. Sleijpen, D. Fokkema C
!!$ C BICGSTAB(L) for linear equations involving unsymmetric C
!!$ C matrices with complex spectrum C
!!$ C Electronic Trans. on Numer. Analysis, Vol. 1, pp. 11-32, C
!!$ C Sep. 1993 C
!!$ C C
!!$ C C
!!$ CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
! File: psb_zcgstabl.f90
!
! Subroutine: psb_zcgstabl
! Implements the BICGSTAB(L) method
!
!
! Arguments:
!
! a - type(psb_zspmat_type) Input: sparse matrix containing A.
! prec - class(psb_zprec_type) Input: preconditioner
! b(:) - complex Input: vector containing the
! right hand side B
! x(:) - complex 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.
! 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.
! irst - integer(optional) Input: restart parameter L
!
!
!
!!$Subroutine psb_zcgstabl(a,prec,b,x,eps,desc_a,info,itmax,iter,err,itrace,irst,istop)
!!$ use psb_base_mod
!!$ use psb_prec_mod
!!$ use psb_z_krylov_conv_mod
!!$ use psb_krylov_mod
!!$ implicit none
!!$
!!$! = parameters
!!$ Type(psb_zspmat_type), Intent(in) :: a
!!$ class(psb_zprec_type), Intent(in) :: prec
!!$ Type(psb_desc_type), Intent(in) :: desc_a
!!$ complex(psb_dpk_), Intent(in) :: b(:)
!!$ complex(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, irst,istop
!!$ integer(psb_ipk_), Optional, Intent(out) :: iter
!!$ Real(psb_dpk_), Optional, Intent(out) :: err
!!$! = local data
!!$ complex(psb_dpk_), allocatable, target :: aux(:),wwrk(:,:),uh(:,:), rh(:,:)
!!$ complex(psb_dpk_), Pointer :: ww(:), q(:), r(:), rt0(:), p(:), v(:), &
!!$ & s(:), t(:), z(:), f(:), gamma(:), gamma1(:), gamma2(:), taum(:,:), sigma(:)
!!$
!!$ integer(psb_ipk_) :: itmax_, naux, mglob, it, itrace_,&
!!$ & np,me, n_row, n_col, nl, err_act
!!$ Logical, Parameter :: exchange=.True., noexchange=.False.
!!$ integer(psb_ipk_), Parameter :: irmax = 8
!!$ integer(psb_ipk_) :: itx, i, isvch, ictxt,istop_,j, int_err(5)
!!$ integer(psb_ipk_) :: debug_level, debug_unit
!!$ complex(psb_dpk_) :: alpha, beta, rho, rho_old, rni, xni, bni, ani,bn2,&
!!$ & omega
!!$ type(psb_itconv_type) :: stopdat
!!$ real(psb_dpk_) :: derr
!!$ character(len=20) :: name
!!$ character(len=*), parameter :: methdname='BiCGStab(L)'
!!$
!!$ info = psb_success_
!!$ name = 'psb_zcgstabl'
!!$ 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
!!$
!!$
!!$ 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
!!$
!!$ if (present(itmax)) then
!!$ itmax_ = itmax
!!$ else
!!$ itmax_ = 1000
!!$ endif
!!$
!!$ if (present(itrace)) then
!!$ itrace_ = itrace
!!$ else
!!$ itrace_ = 0
!!$ end if
!!$
!!$ if (present(irst)) then
!!$ nl = irst
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & 'present: irst: ',irst,nl
!!$ else
!!$ nl = 1
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' not present: irst: ',irst,nl
!!$ endif
!!$ if (nl <=0 ) then
!!$ info=psb_err_invalid_istop_
!!$ int_err(1)=nl
!!$ err=info
!!$ call psb_errpush(info,name,i_err=int_err)
!!$ goto 9999
!!$ endif
!!$
!!$ call psb_chkvect(mglob,ione,size(x,ione),ione,ione,desc_a,info)
!!$ if (info == psb_success_) call psb_chkvect(mglob,ione,size(b,ione),ione,ione,desc_a,info)
!!$ if (info /= psb_success_) then
!!$ info=psb_err_from_subroutine_
!!$ call psb_errpush(info,name,a_err='psb_chkvect on X/B')
!!$ goto 9999
!!$ end if
!!$
!!$ naux=4*n_col
!!$ allocate(aux(naux),gamma(0:nl),gamma1(nl),&
!!$ &gamma2(nl),taum(nl,nl),sigma(nl), stat=info)
!!$
!!$ if (info /= psb_success_) then
!!$ info=psb_err_alloc_dealloc_
!!$ call psb_errpush(info,name)
!!$ goto 9999
!!$ end if
!!$ if (info == psb_success_) Call psb_geall(wwrk,desc_a,info,n=psb_err_iarg_neg_)
!!$ if (info == psb_success_) Call psb_geall(uh,desc_a,info,n=nl+1,lb=0)
!!$ if (info == psb_success_) Call psb_geall(rh,desc_a,info,n=nl+1,lb=0)
!!$ if (info == psb_success_) Call psb_geasb(wwrk,desc_a,info)
!!$ if (info == psb_success_) Call psb_geasb(uh,desc_a,info)
!!$ if (info == psb_success_) Call psb_geasb(rh,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)
!!$ ww => wwrk(:,9)
!!$ rt0 => wwrk(:,10)
!!$
!!$
!!$ call psb_init_conv(methdname,istop_,itrace_,itmax_,a,b,eps,desc_a,stopdat,info)
!!$ if (info /= psb_success_) Then
!!$ call psb_errpush(psb_err_from_subroutine_non_,name)
!!$ goto 9999
!!$ End If
!!$
!!$ itx = 0
!!$ restart: do
!!$! =
!!$! = r0 = b-ax0
!!$! =
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),' restart: ',itx,it
!!$ if (itx >= itmax_) exit restart
!!$
!!$ it = 0
!!$ call psb_geaxpby(zone,b,zzero,r,desc_a,info)
!!$ if (info == psb_success_) call psb_spmm(-zone,a,x,zone,r,desc_a,info,work=aux)
!!$
!!$ if (info == psb_success_) call prec%apply(r,desc_a,info)
!!$
!!$ if (info == psb_success_) call psb_geaxpby(zone,r,zzero,rt0,desc_a,info)
!!$ if (info == psb_success_) call psb_geaxpby(zone,r,zzero,rh(:,0),desc_a,info)
!!$ if (info == psb_success_) call psb_geaxpby(zzero,r,zzero,uh(:,0),desc_a,info)
!!$ if (info /= psb_success_) then
!!$ info=psb_err_from_subroutine_non_
!!$ call psb_errpush(info,name)
!!$ goto 9999
!!$ end if
!!$
!!$ rho = zone
!!$ alpha = zzero
!!$ omega = zone
!!$
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' on entry to amax: b: ',Size(b)
!!$
!!$ if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
!!$ if (info /= psb_success_) Then
!!$ call psb_errpush(psb_err_from_subroutine_non_,name)
!!$ goto 9999
!!$ End If
!!$
!!$ iteration: do
!!$ it = it + nl
!!$ itx = itx + nl
!!$ rho = -omega*rho
!!$
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' iteration: ',itx, rho,rh(1,0)
!!$
!!$ do j = 0, nl -1
!!$ If (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),'bicg part: ',j, nl
!!$
!!$ rho_old = rho
!!$ rho = psb_gedot(rh(:,j),rt0,desc_a,info)
!!$ if (rho == zzero) then
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' bi-cgstab iteration breakdown r',rho
!!$ exit iteration
!!$ endif
!!$
!!$ beta = alpha*rho/rho_old
!!$ rho_old = rho
!!$ call psb_geaxpby(zone,rh(:,0:j),-beta,uh(:,0:j),desc_a,info)
!!$ call psb_spmm(zone,a,uh(:,j),zzero,uh(:,j+1),desc_a,info,work=aux)
!!$
!!$ call prec%apply(uh(:,j+1),desc_a,info)
!!$
!!$ gamma(j) = psb_gedot(uh(:,j+1),rt0,desc_a,info)
!!$
!!$ if (gamma(j) == zzero) then
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' bi-cgstab iteration breakdown s2',gamma(j)
!!$ exit iteration
!!$ endif
!!$ alpha = rho/gamma(j)
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' bicg part: alpha=r/g ',alpha,rho,gamma(j)
!!$
!!$ call psb_geaxpby(-alpha,uh(:,1:j+1),zone,rh(:,0:j),desc_a,info)
!!$ call psb_geaxpby(alpha,uh(:,0),zone,x,desc_a,info)
!!$ call psb_spmm(zone,a,rh(:,j),zzero,rh(:,j+1),desc_a,info,work=aux)
!!$
!!$ call prec%apply(rh(:,j+1),desc_a,info)
!!$
!!$ enddo
!!$
!!$ do j=1, nl
!!$ if (debug_level >= psb_debug_ext_) &
!!$ & write(debug_unit,*) me,' ',trim(name),&
!!$ & ' mod g-s part: ',j, nl,rh(1,0)
!!$
!!$ do i=1, j-1
!!$ taum(i,j) = psb_gedot(rh(:,i),rh(:,j),desc_a,info)
!!$ taum(i,j) = taum(i,j)/sigma(i)
!!$ call psb_geaxpby(-taum(i,j),rh(:,i),zone,rh(:,j),desc_a,info)
!!$ enddo
!!$ sigma(j) = psb_gedot(rh(:,j),rh(:,j),desc_a,info)
!!$ gamma1(j) = psb_gedot(rh(:,0),rh(:,j),desc_a,info)
!!$ gamma1(j) = gamma1(j)/sigma(j)
!!$ enddo
!!$
!!$ gamma(nl) = gamma1(nl)
!!$ omega = gamma(nl)
!!$
!!$ do j=nl-1,1,-1
!!$ gamma(j) = gamma1(j)
!!$ do i=j+1,nl
!!$ gamma(j) = gamma(j) - taum(j,i) * gamma(i)
!!$ enddo
!!$ enddo
!!$
!!$ do j=1,nl-1
!!$ gamma2(j) = gamma(j+1)
!!$ do i=j+1,nl-1
!!$ gamma2(j) = gamma2(j) + taum(j,i) * gamma(i+1)
!!$ enddo
!!$ enddo
!!$
!!$ call psb_geaxpby(gamma(1),rh(:,0),zone,x,desc_a,info)
!!$ call psb_geaxpby(-gamma1(nl),rh(:,nl),zone,rh(:,0),desc_a,info)
!!$ call psb_geaxpby(-gamma(nl),uh(:,nl),zone,uh(:,0),desc_a,info)
!!$
!!$ do j=1, nl-1
!!$ call psb_geaxpby(-gamma(j),uh(:,j),zone,uh(:,0),desc_a,info)
!!$ call psb_geaxpby(gamma2(j),rh(:,j),zone,x,desc_a,info)
!!$ call psb_geaxpby(-gamma1(j),rh(:,j),zone,rh(:,0),desc_a,info)
!!$ enddo
!!$
!!$ if (psb_check_conv(methdname,itx,x,rh(:,0),desc_a,stopdat,info)) exit restart
!!$ if (info /= psb_success_) 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,derr,iter)
!!$
!!$ if (present(err)) then
!!$ err = derr
!!$ end if
!!$
!!$ deallocate(aux,stat=info)
!!$ if (info == psb_success_) call psb_gefree(wwrk,desc_a,info)
!!$ if (info == psb_success_) call psb_gefree(uh,desc_a,info)
!!$ if (info == psb_success_) call psb_gefree(rh,desc_a,info)
!!$ if (info /= psb_success_) then
!!$ call psb_errpush(info,name)
!!$ goto 9999
!!$ end if
!!$
!!$ call psb_erractionrestore(err_act)
!!$ return
!!$
!!$9999 continue
!!$ call psb_erractionrestore(err_act)
!!$ if (err_act == psb_act_abort_) then
!!$ call psb_error()
!!$ return
!!$ end if
!!$ return
!!$
!!$End Subroutine psb_zcgstabl
!!$
Subroutine psb_zcgstabl_vect(a,prec,b,x,eps,desc_a,info,&
& itmax,iter,err,itrace,irst,istop)
use psb_base_mod
use psb_prec_mod
use psb_z_krylov_conv_mod
use psb_krylov_mod
implicit none
type(psb_zspmat_type), intent(in) :: a
class(psb_zprec_type), Intent(inout) :: prec
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_z_vect_type), Intent(inout) :: b
type(psb_z_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, irst,istop
integer(psb_ipk_), Optional, Intent(out) :: iter
Real(psb_dpk_), Optional, Intent(out) :: err
! = local data
complex(psb_dpk_), allocatable, target :: aux(:), gamma(:),&
& gamma1(:), gamma2(:), taum(:,:), sigma(:)
type(psb_z_vect_type), allocatable, target :: wwrk(:),uh(:), rh(:)
type(psb_z_vect_type), Pointer :: ww, q, r, rt0, p, v, &
& s, t, z, f
integer(psb_ipk_) :: itmax_, naux, mglob, it, itrace_,&
& n_row, n_col, nl, err_act
Logical, Parameter :: exchange=.True., noexchange=.False.
integer(psb_ipk_), Parameter :: irmax = 8
integer(psb_ipk_) :: itx, i, istop_,j, k, int_err(5)
integer(psb_ipk_) :: debug_level, debug_unit
integer(psb_ipk_) :: ictxt, np, me
complex(psb_dpk_) :: alpha, beta, rho, rho_old, rni, xni, bni, ani,bn2,&
& omega
real(psb_dpk_) :: derr
type(psb_itconv_type) :: stopdat
character(len=20) :: name
character(len=*), parameter :: methdname='BiCGStab(L)'
info = psb_success_
name = 'psb_zcgstabl'
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
if (present(itmax)) then
itmax_ = itmax
else
itmax_ = 1000
endif
if (present(itrace)) then
itrace_ = itrace
else
itrace_ = 0
end if
if (present(irst)) then
nl = irst
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& 'present: irst: ',irst,nl
else
nl = 1
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' not present: irst: ',irst,nl
endif
if (nl <=0 ) then
info=psb_err_invalid_istop_
int_err(1)=nl
err=info
call psb_errpush(info,name,i_err=int_err)
goto 9999
endif
call psb_chkvect(mglob,ione,x%get_nrows(),ione,ione,desc_a,info)
if (info == psb_success_) call psb_chkvect(mglob,ione,b%get_nrows(),ione,ione,desc_a,info)
if (info /= psb_success_) then
info=psb_err_from_subroutine_
call psb_errpush(info,name,a_err='psb_chkvect on X/B')
goto 9999
end if
naux=4*n_col
allocate(aux(naux),gamma(0:nl),gamma1(nl),&
&gamma2(nl),taum(nl,nl),sigma(nl), stat=info)
if (info /= psb_success_) then
info=psb_err_alloc_dealloc_
call psb_errpush(info,name)
goto 9999
end if
if (info == psb_success_) Call psb_geall(wwrk,desc_a,info,n=10_psb_ipk_)
if (info == psb_success_) Call psb_geall(uh,desc_a,info,n=nl+1,lb=izero)
if (info == psb_success_) Call psb_geall(rh,desc_a,info,n=nl+1,lb=izero)
if (info == psb_success_) Call psb_geasb(wwrk,desc_a,info,mold=x%v)
if (info == psb_success_) Call psb_geasb(uh,desc_a,info,mold=x%v)
if (info == psb_success_) Call psb_geasb(rh,desc_a,info,mold=x%v)
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)
ww => wwrk(9)
rt0 => wwrk(10)
call psb_init_conv(methdname,istop_,itrace_,itmax_,a,b,eps,desc_a,stopdat,info)
if (info /= psb_success_) Then
call psb_errpush(psb_err_from_subroutine_non_,name)
goto 9999
End If
itx = 0
restart: do
! =
! = r0 = b-ax0
! =
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),' restart: ',itx,it
if (itx >= itmax_) exit restart
it = 0
call psb_geaxpby(zone,b,zzero,r,desc_a,info)
if (info == psb_success_) call psb_spmm(-zone,a,x,zone,r,desc_a,info,work=aux)
if (info == psb_success_) call prec%apply(r,desc_a,info)
if (info == psb_success_) call psb_geaxpby(zone,r,zzero,rt0,desc_a,info)
if (info == psb_success_) call psb_geaxpby(zone,r,zzero,rh(0),desc_a,info)
if (info == psb_success_) call psb_geaxpby(zzero,r,zzero,uh(0),desc_a,info)
if (info /= psb_success_) then
info=psb_err_from_subroutine_non_
call psb_errpush(info,name)
goto 9999
end if
rho = zone
alpha = zzero
omega = zone
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' on entry to amax: b: ',b%get_nrows()
if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
if (info /= psb_success_) Then
call psb_errpush(psb_err_from_subroutine_non_,name)
goto 9999
End If
iteration: do
it = it + nl
itx = itx + nl
rho = -omega*rho
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' iteration: ',itx, rho
do j = 0, nl -1
If (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),'bicg part: ',j, nl
rho_old = rho
rho = psb_gedot(rh(j),rt0,desc_a,info)
if (rho == zzero) then
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' bi-cgstab iteration breakdown r',rho
exit iteration
endif
beta = alpha*rho/rho_old
rho_old = rho
do k=0, j
! = call psb_geaxpby(zone,rh(:,0:j),-beta,uh(:,0:j),desc_a,info)
call psb_geaxpby(zone,rh(k),-beta,uh(k),desc_a,info)
end do
call psb_spmm(zone,a,uh(j),zzero,uh(j+1),desc_a,info,work=aux)
call prec%apply(uh(j+1),desc_a,info)
gamma(j) = psb_gedot(uh(j+1),rt0,desc_a,info)
if (gamma(j) == zzero) then
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' bi-cgstab iteration breakdown s2',gamma(j)
exit iteration
endif
alpha = rho/gamma(j)
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' bicg part: alpha=r/g ',alpha,rho,gamma(j)
do k=0,j
! = call psb_geaxpby(-alpha,uh(:,1:j+1),zone,rh(:,0:j),desc_a,info)
call psb_geaxpby(-alpha,uh(k+1),zone,rh(k),desc_a,info)
end do
call psb_geaxpby(alpha,uh(0),zone,x,desc_a,info)
call psb_spmm(zone,a,rh(j),zzero,rh(j+1),desc_a,info,work=aux)
call prec%apply(rh(j+1),desc_a,info)
enddo
do j=1, nl
if (debug_level >= psb_debug_ext_) &
& write(debug_unit,*) me,' ',trim(name),&
& ' mod g-s part: ',j, nl
do i=1, j-1
taum(i,j) = psb_gedot(rh(i),rh(j),desc_a,info)
taum(i,j) = taum(i,j)/sigma(i)
call psb_geaxpby(-taum(i,j),rh(i),zone,rh(j),desc_a,info)
enddo
sigma(j) = psb_gedot(rh(j),rh(j),desc_a,info)
gamma1(j) = psb_gedot(rh(0),rh(j),desc_a,info)
gamma1(j) = gamma1(j)/sigma(j)
enddo
gamma(nl) = gamma1(nl)
omega = gamma(nl)
do j=nl-1,1,-1
gamma(j) = gamma1(j)
do i=j+1,nl
gamma(j) = gamma(j) - taum(j,i) * gamma(i)
enddo
enddo
do j=1,nl-1
gamma2(j) = gamma(j+1)
do i=j+1,nl-1
gamma2(j) = gamma2(j) + taum(j,i) * gamma(i+1)
enddo
enddo
call psb_geaxpby(gamma(1),rh(0),zone,x,desc_a,info)
call psb_geaxpby(-gamma1(nl),rh(nl),zone,rh(0),desc_a,info)
call psb_geaxpby(-gamma(nl),uh(nl),zone,uh(0),desc_a,info)
do j=1, nl-1
call psb_geaxpby(-gamma(j),uh(j),zone,uh(0),desc_a,info)
call psb_geaxpby(gamma2(j),rh(j),zone,x,desc_a,info)
call psb_geaxpby(-gamma1(j),rh(j),zone,rh(0),desc_a,info)
enddo
if (psb_check_conv(methdname,itx,x,rh(0),desc_a,stopdat,info)) exit restart
if (info /= psb_success_) 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,derr,iter)
if (present(err)) err = derr
if (info == psb_success_) call psb_gefree(uh,desc_a,info)
if (info == psb_success_) call psb_gefree(rh,desc_a,info)
if (info == psb_success_) call psb_gefree(wwrk,desc_a,info)
if (info == psb_success_) deallocate(aux,stat=info)
if (info /= psb_success_) then
call psb_errpush(info,name)
goto 9999
end if
call psb_erractionrestore(err_act)
return
9999 continue
call psb_erractionrestore(err_act)
if (err_act == psb_act_abort_) then
call psb_error()
return
end if
return
End Subroutine psb_zcgstabl_vect