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psblas3/krylov/psb_scgstabl.f90

422 lines
16 KiB
Fortran

!
! 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.
!
!
! 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_scgstabl.f90
!
! Subroutine: psb_scgstabl
! Implements the BICGSTAB(L) method
!
!
! Arguments:
!
! a - type(psb_sspmat_type) Input: sparse matrix containing A.
! prec - class(psb_sprec_type) Input: preconditioner
! b(:) - real Input: vector containing the
! right hand side B
! x(:) - real 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_scgstabl_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_s_krylov_conv_mod
use psb_krylov_mod
implicit none
type(psb_sspmat_type), intent(in) :: a
class(psb_sprec_type), Intent(inout) :: prec
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_s_vect_type), Intent(inout) :: b
type(psb_s_vect_type), Intent(inout) :: x
Real(psb_spk_), 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_spk_), Optional, Intent(out) :: err
! = local data
real(psb_spk_), allocatable, target :: aux(:), gamma(:),&
& gamma1(:), gamma2(:), taum(:,:), sigma(:)
type(psb_s_vect_type), allocatable, target :: wwrk(:),uh(:), rh(:)
type(psb_s_vect_type), Pointer :: ww, q, r, rt0, p, v, &
& s, t, z, f
integer(psb_ipk_) :: itmax_, naux, it, itrace_,&
& n_row, n_col, nl, err_act
integer(psb_lpk_) :: mglob
Logical, Parameter :: exchange=.True., noexchange=.False.
integer(psb_ipk_), Parameter :: irmax = 8
integer(psb_ipk_) :: itx, i, istop_,j, k
integer(psb_ipk_) :: debug_level, debug_unit
type(psb_ctxt_type) :: ctxt
integer(psb_ipk_) :: np, me
real(psb_spk_) :: 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_scgstabl'
call psb_erractionsave(err_act)
debug_unit = psb_get_debug_unit()
debug_level = psb_get_debug_level()
ctxt = desc_a%get_context()
Call psb_info(ctxt, 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_irst_
err=info
call psb_errpush(info,name,i_err=(/nl/))
goto 9999
endif
call psb_chkvect(mglob,lone,x%get_nrows(),lone,lone,desc_a,info)
if (info == psb_success_) call psb_chkvect(mglob,lone,b%get_nrows(),lone,lone,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,x,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(sone,b,szero,r,desc_a,info)
if (info == psb_success_) call psb_spmm(-sone,a,x,sone,r,desc_a,info,work=aux)
if (info == psb_success_) call prec%apply(r,desc_a,info)
if (info == psb_success_) call psb_geaxpby(sone,r,szero,rt0,desc_a,info)
if (info == psb_success_) call psb_geaxpby(sone,r,szero,rh(0),desc_a,info)
if (info == psb_success_) call psb_geaxpby(szero,r,szero,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 = sone
alpha = szero
omega = sone
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 == szero) 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(sone,rh(:,0:j),-beta,uh(:,0:j),desc_a,info)
call psb_geaxpby(sone,rh(k),-beta,uh(k),desc_a,info)
end do
call psb_spmm(sone,a,uh(j),szero,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) == szero) 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),sone,rh(:,0:j),desc_a,info)
call psb_geaxpby(-alpha,uh(k+1),sone,rh(k),desc_a,info)
end do
call psb_geaxpby(alpha,uh(0),sone,x,desc_a,info)
call psb_spmm(sone,a,rh(j),szero,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),sone,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),sone,x,desc_a,info)
call psb_geaxpby(-gamma1(nl),rh(nl),sone,rh(0),desc_a,info)
call psb_geaxpby(-gamma(nl),uh(nl),sone,uh(0),desc_a,info)
do j=1, nl-1
call psb_geaxpby(-gamma(j),uh(j),sone,uh(0),desc_a,info)
call psb_geaxpby(gamma2(j),rh(j),sone,x,desc_a,info)
call psb_geaxpby(-gamma1(j),rh(j),sone,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 call psb_error_handler(err_act)
return
End Subroutine psb_scgstabl_vect