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psblas3/krylov/psb_dcgstab.f90

392 lines
14 KiB
Fortran

!
! Parallel Sparse BLAS version 3.4
! (C) Copyright 2006, 2010, 2015
! 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.
! 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_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_krylov_conv_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_,&
& 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, err_act, i
integer(psb_ipk_) :: istop_
integer(psb_ipk_) :: ictxt, np, me
real(psb_dpk_) :: derr
real(psb_dpk_) :: alpha, beta, rho, rho_old, sigma, omega, tau
type(psb_itconv_type) :: stopdat
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,ione,x%get_nrows(),ione,ione,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,ione,b%get_nrows(),ione,ione,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
itx = 0
call psb_init_conv(methdname,istop_,itrace_,itmax_,a,x,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
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
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
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,derr,iter)
if (present(err)) err = derr
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
call psb_erractionrestore(err_act)
return
9999 call psb_error_handler(err_act)
return
End Subroutine psb_dcgstab_vect