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psblas3/krylov/psb_skrylov.f90

229 lines
9.9 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.
!
!
!
! File: psb_krylov_mod.f90
! Interfaces for Krylov subspace iterative methods.
!
!
! Subroutine: psb_skrylov
!
! Front-end for the Krylov subspace iterations, realversion
!
! Arguments:
!
! methd - character The specific method; can take the values:
! CG
! CGS
! BICG
! BICGSTAB
! BICGSTABL
! RGMRES
!
! a - type(psb_sspmat_type) Input: sparse matrix containing A.
! prec - class(psb_sprec_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
! itrace - integer(optional) Input: print an informational message
! with the error estimate every itrace
! iterations
! irst - integer(optional) Input: restart parameter for RGMRES and
! BICGSTAB(L) methods
! istop - integer(optional) Input: stopping criterion, or how
! to estimate the error.
! 1: err = |r|/(|a||x|+|b|)
! 2: err = |r|/|b|
! where r is the (preconditioned, recursive
! estimate of) residual
!
Subroutine psb_skrylov_vect(method,a,prec,b,x,eps,desc_a,info,&
& itmax,iter,err,itrace,irst,istop,cond)
use psb_base_mod
use psb_prec_mod,only : psb_sprec_type
use psb_krylov_mod, psb_protect_name => psb_skrylov_vect
character(len=*) :: method
Type(psb_sspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_sprec_type), intent(inout) :: prec
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,cond
abstract interface
subroutine psb_skryl_vect(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
import :: psb_ipk_, psb_spk_, psb_desc_type, &
& psb_sspmat_type, psb_sprec_type, psb_s_vect_type
type(psb_sspmat_type), intent(in) :: a
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
class(psb_sprec_type), intent(inout) :: prec
integer(psb_ipk_), intent(out) :: info
integer(psb_ipk_), optional, intent(in) :: itmax, itrace,istop
integer(psb_ipk_), optional, intent(out) :: iter
real(psb_spk_), optional, intent(out) :: err
end subroutine psb_skryl_vect
Subroutine psb_skryl_rest_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err, itrace,irst,istop)
import :: psb_ipk_, psb_spk_, psb_desc_type, &
& psb_sspmat_type, psb_sprec_type, psb_s_vect_type
Type(psb_sspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_sprec_type), intent(inout) :: prec
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
end subroutine psb_skryl_rest_vect
Subroutine psb_skryl_cond_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err, itrace,istop,cond)
import :: psb_ipk_, psb_spk_, psb_desc_type, &
& psb_sspmat_type, psb_sprec_type, psb_s_vect_type
Type(psb_sspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_sprec_type), intent(inout) :: prec
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,istop
integer(psb_ipk_), Optional, Intent(out) :: iter
Real(psb_spk_), Optional, Intent(out) :: err, cond
end subroutine psb_skryl_cond_vect
end interface
procedure(psb_skryl_vect) :: psb_sbicg_vect, psb_scgstab_vect,&
& psb_scgs_vect
procedure(psb_skryl_rest_vect) :: psb_srgmres_vect, psb_scgstabl_vect, psb_sgcr_vect
procedure(psb_skryl_cond_vect) :: psb_scg_vect, psb_sfcg_vect
logical :: do_alloc_wrk
type(psb_ctxt_type) :: ctxt
integer(psb_ipk_) :: me,np,err_act, itrace_
character(len=20) :: name
info = psb_success_
name = 'psb_krylov'
call psb_erractionsave(err_act)
ctxt=desc_a%get_context()
call psb_info(ctxt, me, np)
! Default return for COND
if (present(cond)) cond = szero
if (present(itrace)) then
itrace_ = itrace
else
itrace_ = -1
end if
do_alloc_wrk = .not.prec%is_allocated_wrk()
if (do_alloc_wrk) call prec%allocate_wrk(info,vmold=x%v,desc=desc_a)
select case(psb_toupper(method))
case('CG')
call psb_scg_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop,cond=cond)
case('FCG')
call psb_sfcg_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop,cond=cond)
case('GCR')
call psb_sgcr_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop)
case('CGS')
call psb_scgs_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop)
case('BICG')
call psb_sbicg_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop)
case('BICGSTAB')
call psb_scgstab_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop)
case('RGMRES','GMRES')
call psb_srgmres_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,irst=irst,istop=istop)
case('BICGSTABL')
call psb_scgstabl_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,irst=irst,istop=istop)
case default
if (me == 0) write(psb_err_unit,*) trim(name),&
& ': Warning: Unknown method ',method,&
& ', defaulting to BiCGSTAB'
call psb_scgstab_vect(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace=itrace_,istop=istop)
end select
if ((info==psb_success_).and.do_alloc_wrk) call prec%free_wrk(info)
if(info /= psb_success_) then
info = psb_err_from_subroutine_
call psb_errpush(info,name,a_err=trim(method))
goto 9999
end if
call psb_erractionrestore(err_act)
return
9999 call psb_error_handler(ctxt,err_act)
return
end subroutine psb_skrylov_vect