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psblas3/krylov/psb_skrylov.f90

250 lines
11 KiB
Fortran

!!$
!!$ 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
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!!$ 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, real version
!
! 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|/|b|
! 2: err = |r|/(|a||x|+|b|)
! where r is the (preconditioned, recursive
! estimate of) residual
!
Subroutine psb_skrylov(method,a,prec,b,x,eps,desc_a,info,itmax,iter,err,itrace,irst,istop,cond)
use psb_sparse_mod
use psb_prec_mod,only : psb_sprec_type, psb_dprec_type, psb_cprec_type, psb_zprec_type
use psb_krylov_mod, psb_protect_name => psb_skrylov
character(len=*) :: method
Type(psb_sspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_sprec_type), intent(in) :: prec
Real(psb_spk_), Intent(in) :: b(:)
Real(psb_spk_), Intent(inout) :: x(:)
Real(psb_spk_), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(psb_spk_), Optional, Intent(out) :: err,cond
interface
subroutine psb_scg(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop,cond)
use psb_sparse_mod, only : psb_desc_type, psb_sspmat_type, psb_spk_
use psb_prec_mod, only : psb_sprec_type
type(psb_sspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
real(psb_spk_), intent(in) :: b(:)
real(psb_spk_), intent(inout) :: x(:)
real(psb_spk_), intent(in) :: eps
class(psb_sprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(psb_spk_), optional, intent(out) :: err,cond
end subroutine psb_scg
subroutine psb_sbicg(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_sparse_mod, only : psb_desc_type, psb_sspmat_type, psb_spk_
use psb_prec_mod, only : psb_sprec_type
type(psb_sspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
real(psb_spk_), intent(in) :: b(:)
real(psb_spk_), intent(inout) :: x(:)
real(psb_spk_), intent(in) :: eps
class(psb_sprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(psb_spk_), optional, intent(out) :: err
end subroutine psb_sbicg
subroutine psb_scgstab(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_sparse_mod, only : psb_desc_type, psb_sspmat_type, psb_spk_
use psb_prec_mod, only : psb_sprec_type
type(psb_sspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
real(psb_spk_), intent(in) :: b(:)
real(psb_spk_), intent(inout) :: x(:)
real(psb_spk_), intent(in) :: eps
class(psb_sprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(psb_spk_), optional, intent(out) :: err
end subroutine psb_scgstab
Subroutine psb_scgstabl(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err, itrace,irst,istop)
use psb_sparse_mod, only : psb_desc_type, psb_sspmat_type, psb_spk_
use psb_prec_mod, only : psb_sprec_type
Type(psb_sspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_sprec_type), intent(in) :: prec
Real(psb_spk_), Intent(in) :: b(:)
Real(psb_spk_), Intent(inout) :: x(:)
Real(psb_spk_), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(psb_spk_), Optional, Intent(out) :: err
end subroutine psb_scgstabl
Subroutine psb_srgmres(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
use psb_sparse_mod, only : psb_desc_type, psb_sspmat_type, psb_spk_
use psb_prec_mod, only : psb_sprec_type
Type(psb_sspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_sprec_type), intent(in) :: prec
Real(psb_spk_), Intent(in) :: b(:)
Real(psb_spk_), Intent(inout) :: x(:)
Real(psb_spk_), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(psb_spk_), Optional, Intent(out) :: err
end subroutine psb_srgmres
subroutine psb_scgs(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
use psb_sparse_mod, only : psb_desc_type, psb_sspmat_type, psb_spk_
use psb_prec_mod, only : psb_sprec_type
type(psb_sspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
class(psb_sprec_type), intent(in) :: prec
real(psb_spk_), intent(in) :: b(:)
real(psb_spk_), intent(inout) :: x(:)
real(psb_spk_), intent(in) :: eps
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(psb_spk_), optional, intent(out) :: err
end subroutine psb_scgs
end interface
integer :: ictxt,me,np,err_act
character(len=20) :: name
info = psb_success_
name = 'psb_krylov'
call psb_erractionsave(err_act)
ictxt=psb_cd_get_context(desc_a)
call psb_info(ictxt, me, np)
select case(psb_toupper(method))
case('CG')
call psb_scg(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop,cond)
case('CGS')
call psb_scgs(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('BICG')
call psb_sbicg(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('BICGSTAB')
call psb_scgstab(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('RGMRES')
call psb_srgmres(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
case('BICGSTABL')
call psb_scgstabl(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
case default
if (me == 0) write(psb_err_unit,*) trim(name),': Warning: Unknown method ',method,&
& ', defaulting to BiCGSTAB'
call psb_scgstab(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
end select
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(ictxt)
return
end if
end subroutine psb_skrylov