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amg4psblas/krylov/mld_krylov_mod.f90

461 lines
18 KiB
Fortran

!!$
!!$
!!$ MLD2P4
!!$ MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$ based on PSBLAS (Parallel Sparse BLAS v.2.0)
!!$
!!$ (C) Copyright 2006 Alfredo Buttari University of Rome Tor Vergata
!!$ Pasqua D'Ambra ICAR-CNR, Naples
!!$ Daniela di Serafino Second University of Naples
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$
!!$ 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 MLD2P4 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 MLD2P4 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: mld_krylov_mod.f90.
!
! Module: mld_krylov_mod.
! Contains: mld_dkrylov, mld_zkrylov.
!
! This module defines the interfaces to the real and complex versions of the
! routines implementing Krylov solvers:
! - mld_krylov : driver providing a general interface to the Krylov
! solvers available in PSBLAS;
! - psb_cg : Conjugate Gradient (CG) solver (real version only);
! - psb_bicg : BiConjugate Gradient (BiCG) solver (real version only);
! - psb_bicgstab : BiConjugate Gradient Stabilized (BiCGStab) solver;
! - psb_bicgstabl : BiCGStab(l) solver (real version only);
! - psb_rgmres : Generalized Minimal Residual (GMRES) solver with
! Restarting;
! - psb_cgs : Conjugate Gradient Squared (CGS) solver.
!
! This is a partial duplication of material already present in the Krylov
! part of the PSBLAS subtree. This is not bad since
! 1. there is no actual computation here, these are just wrappers around
! the actual methods, so very little code is necessary;
! 2. these wrappers enable issuing error messages with a subroutine name
! coherent with what the user sees;
! 3. at the very least we would need a layer renaming the PSBLAS krylov
! interfaces, so we are doing approximately the same amount of (re)coding.
!
Module mld_krylov_mod
interface mld_krylov
module procedure mld_dkrylov, mld_zkrylov
end interface
interface psb_cg
subroutine psb_dcg(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
type(psb_dspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
real(kind(1.d0)), intent(in) :: b(:)
real(kind(1.d0)), intent(inout) :: x(:)
real(kind(1.d0)), intent(in) :: eps
type(psb_dprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(kind(1.d0)), optional, intent(out) :: err
end subroutine psb_dcg
end interface
interface psb_bicg
subroutine psb_dbicg(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
type(psb_dspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
real(kind(1.d0)), intent(in) :: b(:)
real(kind(1.d0)), intent(inout) :: x(:)
real(kind(1.d0)), intent(in) :: eps
type(psb_dprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(kind(1.d0)), optional, intent(out) :: err
end subroutine psb_dbicg
end interface
interface psb_bicgstab
subroutine psb_dcgstab(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
type(psb_dspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
real(kind(1.d0)), intent(in) :: b(:)
real(kind(1.d0)), intent(inout) :: x(:)
real(kind(1.d0)), intent(in) :: eps
type(psb_dprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(kind(1.d0)), optional, intent(out) :: err
end subroutine psb_dcgstab
subroutine psb_zcgstab(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
type(psb_zspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
complex(kind(1.d0)), intent(in) :: b(:)
complex(kind(1.d0)), intent(inout) :: x(:)
real(kind(1.d0)), intent(in) :: eps
type(psb_zprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(kind(1.d0)), optional, intent(out) :: err
end subroutine psb_zcgstab
end interface
interface psb_bicgstabl
Subroutine psb_dcgstabl(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err, itrace,irst,istop)
use psb_base_mod
use psb_prec_mod
Type(psb_dspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_dprec_type), intent(in) :: prec
Real(Kind(1.d0)), Intent(in) :: b(:)
Real(Kind(1.d0)), Intent(inout) :: x(:)
Real(Kind(1.d0)), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(Kind(1.d0)), Optional, Intent(out) :: err
end subroutine psb_dcgstabl
end interface
interface psb_rgmres
Subroutine psb_dgmresr(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
use psb_base_mod
use psb_prec_mod
Type(psb_dspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_dprec_type), intent(in) :: prec
Real(Kind(1.d0)), Intent(in) :: b(:)
Real(Kind(1.d0)), Intent(inout) :: x(:)
Real(Kind(1.d0)), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(Kind(1.d0)), Optional, Intent(out) :: err
end subroutine psb_dgmresr
Subroutine psb_zgmresr(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
use psb_base_mod
use psb_prec_mod
Type(psb_zspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_zprec_type), intent(in) :: prec
complex(Kind(1.d0)), Intent(in) :: b(:)
complex(Kind(1.d0)), Intent(inout) :: x(:)
Real(Kind(1.d0)), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(Kind(1.d0)), Optional, Intent(out) :: err
end subroutine psb_zgmresr
end interface
interface psb_cgs
subroutine psb_dcgs(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
type(psb_dspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
type(psb_dprec_type), intent(in) :: prec
real(kind(1.d0)), intent(in) :: b(:)
real(kind(1.d0)), intent(inout) :: x(:)
real(kind(1.d0)), intent(in) :: eps
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(kind(1.d0)), optional, intent(out) :: err
end subroutine psb_dcgs
subroutine psb_zcgs(a,prec,b,x,eps,&
& desc_a,info,itmax,iter,err,itrace,istop)
use psb_base_mod
use psb_prec_mod
type(psb_zspmat_type), intent(in) :: a
type(psb_desc_type), intent(in) :: desc_a
complex(kind(1.d0)), intent(in) :: b(:)
complex(kind(1.d0)), intent(inout) :: x(:)
real(kind(1.d0)), intent(in) :: eps
type(psb_zprec_type), intent(in) :: prec
integer, intent(out) :: info
integer, optional, intent(in) :: itmax, itrace,istop
integer, optional, intent(out) :: iter
real(kind(1.d0)), optional, intent(out) :: err
end subroutine psb_zcgs
end interface
contains
!
! Subroutine: mld_dkrylov/mld_zkrylov.
! Version: real/complex.
! Note: internal subroutine of module mld_krylov_mod.
!
! This routine solves a linear system
!
! Ax = b
!
! by using one of following preconditioned Krylov solvers: CG, BiCG, BiCGStab,
! BiCGStab(l), Restarted GMRES, CGS. The preconditioning is applied as right
! preconditioning.
!
! The user can choose among two stopping criteria:
!
! - one based on the normwise backward error in the infinity norm, i.e.
!
! ||r_i||_inf < eps * (||A||_inf * ||x_i||_inf + ||b||_inf);
!
! - the other based on the relative residual reduction in the 2-norm, i.e.
!
! ||r_i||_2 < eps * ||b||_2.
!
! In the above formulae, x_i is the approximate solution and r_i = b - A*x_i
! is the corresponding residual at the i-th iteration.
!
! This routine is a driver that provides a general interface to the Krylov
! solvers implemented in PSBLAS. These solvers can use all the preconditioners
! available in MLD2P4.
!
!
! Arguments:
! method - character(len=*), input.
! The Krylov method to be applied. The following values are
! are allowed in the real case: 'cg', 'bicg', 'bicgstab',
! 'bicgstabl', 'rgmres', 'cgs' (and all the upper/lower case
! variants). The same values except 'cg', 'bicg' and 'bicgstabl'
! are allowed in the complex case.
! a - type(psb_dspmat_type)/type(psb_zspmat_type), input.
! The sparse matrix structure containing the local part of the
! matrix A.
! prec - type(mld_dprec_type)/type(mld_zprec_type), input.
! The preconditioner data structure containing the local part
! of the preconditioner to be applied.
! b - real(kind(1.d0))/complex(kind(1.d0)), dimension(:), input.
! The local part of the right-hand side.
! x - real(kind(1.d0))/complex(kind(1.d0)), dimension(:), input/output.
! The local part of the approximate solution. In input it
! contains an initial guess of the solution, while, in output,
! the approximation computed by the selected Krylov solver.
! eps - real(kind(1.d0)), input.
! The tolerance used in the stopping criterion.
! desc_a - type(psb_desc_type), input.
! The communication descriptor associated to a.
! info - integer, output.
! Error code.
! itmax - integer, optional, input.
! The maximum number of iterations to be performed. If itmax
! is not present, a maximum number of 1000 iterations is
! assumed.
! iter - integer, optional, output.
! The number of iterations actually performed.
! err - real(kind(1.d0)), optional, output.
! An estimate of the error in the computed solution, i.e. the
! relative backward error ||r|| / (||A||*||x||+||b||), where
! || || is the infinity norm, or the relative residual
! ||r||/||b||, where || || is the 2-norm, according to the
! selected stopping criterion (see istop below).
! itrace - integer, optional, input.
! If itrace>0 then information about convergence is printed
! every itrace iterations; otherwise it is ignored. If itrace
! is not present, itrace=0 is assumed.
! irst - integer, optional, input.
! The restart parameter used in the GMRES and BiCGSTAB(l)
! solvers. It is ignored if other solvers are chosen. If irst
! is not present, irst=10 is assumed for Restarded GMRES and
! irst=l=1 for BiCGStab(l) (note that BiCGStab(1)=BiCGStab).
! istop - integer, optional, input.
! The normwise backward error stopping criterion is used if
! istop=1; the relative residual one if istop=2. If istop
! is not present, istop=1 is assumed.
!
Subroutine mld_dkrylov(method,a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
use psb_base_mod
use psb_prec_mod
! Arguments
character(len=*) :: method
Type(psb_dspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_dprec_type), intent(in) :: prec
Real(Kind(1.d0)), Intent(in) :: b(:)
Real(Kind(1.d0)), Intent(inout) :: x(:)
Real(Kind(1.d0)), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(Kind(1.d0)), Optional, Intent(out) :: err
! Local variables
integer :: ictxt,me,np,err_act
character(len=20) :: name
info = 0
name = 'mld_krylov'
call psb_erractionsave(err_act)
ictxt=psb_cd_get_context(desc_a)
call psb_info(ictxt, me, np)
select case(toupper(method))
case('CG')
call psb_cg(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('CGS')
call psb_cgs(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('BICG')
call psb_bicg(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('BICGSTAB')
call psb_bicgstab(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
case('RGMRES')
call psb_rgmres(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
case('BICGSTABL')
call psb_bicgstabl(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
case default
if (me==0) write(0,*) 'Warning: Unknown method ',method,&
& ' in ',name,' defaulting to BiCGSTAB'
call psb_bicgstab(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
end select
if(info/=0) 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.eq.psb_act_abort_) then
call psb_error(ictxt)
return
end if
end subroutine mld_dkrylov
Subroutine mld_zkrylov(method,a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,irst,istop)
use psb_base_mod
use psb_prec_mod
! Arguments
character(len=*) :: method
Type(psb_zspmat_type), Intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
type(psb_zprec_type), intent(in) :: prec
complex(Kind(1.d0)), Intent(in) :: b(:)
complex(Kind(1.d0)), Intent(inout) :: x(:)
Real(Kind(1.d0)), Intent(in) :: eps
integer, intent(out) :: info
Integer, Optional, Intent(in) :: itmax, itrace, irst,istop
Integer, Optional, Intent(out) :: iter
Real(Kind(1.d0)), Optional, Intent(out) :: err
! Local variables
integer :: ictxt,me,np,err_act
character(len=20) :: name
info = 0
name = 'mld_krylov'
call psb_erractionsave(err_act)
ictxt=psb_cd_get_context(desc_a)
call psb_info(ictxt, me, np)
select case(toupper(method))
!!$ case('CG')
!!$ call psb_cg(a,prec,b,x,eps,desc_a,info,&
!!$ &itmax,iter,err,itrace,istop)
case('CGS')
call psb_cgs(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
!!$ case('BICG')
!!$ call psb_bicg(a,prec,b,x,eps,desc_a,info,&
!!$ &itmax,iter,err,itrace,istop)
case('BICGSTAB')
call psb_bicgstab(a,prec,b,x,eps,desc_a,info,&
& itmax,iter,err,itrace,istop)
case('RGMRES')
call psb_rgmres(a,prec,b,x,eps,desc_a,info,&
& itmax,iter,err,itrace,irst,istop)
!!$ case('BICGSTABL')
!!$ call psb_bicgstabl(a,prec,b,x,eps,desc_a,info,&
!!$ &itmax,iter,err,itrace,irst,istop)
case default
if (me==0) write(0,*) 'Warning: Unknown method ',method,&
& ' in ',name,' defaulting to BiCGSTAB'
call psb_bicgstab(a,prec,b,x,eps,desc_a,info,&
&itmax,iter,err,itrace,istop)
end select
if(info/=0) 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.eq.psb_act_abort_) then
call psb_error(ictxt)
return
end if
end subroutine mld_zkrylov
end module mld_krylov_mod