You cannot select more than 25 topics Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
psblas3/krylov/psb_cgcr.f90

371 lines
13 KiB
Fortran

This file contains ambiguous Unicode characters!

This file contains ambiguous Unicode characters that may be confused with others in your current locale. If your use case is intentional and legitimate, you can safely ignore this warning. Use the Escape button to highlight these characters.

!
! 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_cgcr.f90
!!
!! Contributors: Ambra Abdullahi (UNITOV) and Pasqua DAmbra (IAC-CNR)
!!
! 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 [4] Notay, Yvan C
! C Aggregation-based algebraic multigrid method C
! C SIAM Journal on Scientific Computing 34, C
! C pp. A2288-A2316, 2012 C
! C C
! C C
! CCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCCC
! File: psb_cgcr.f90
!
! Subroutine: psb_cgcr
! This subroutine implements the GCR method.
!
!
! Arguments:
!
! a - type(psb_cspmat_type) Input: sparse matrix containing A.
! prec - class(psb_cprec_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
!
subroutine psb_cgcr_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_c_krylov_conv_mod
use psb_krylov_mod
implicit none
type(psb_cspmat_type), intent(in) :: a
Type(psb_desc_type), Intent(in) :: desc_a
class(psb_cprec_type), intent(inout) :: prec
type(psb_c_vect_type), Intent(inout) :: b
type(psb_c_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
complex(psb_spk_), allocatable :: alpha(:), h(:,:)
type(psb_c_vect_type), allocatable :: z(:), c(:), c_scale(:)
type(psb_c_vect_type) :: r
real(psb_dpk_) :: r_norm, b_norm, a_norm, derr
integer(psb_ipk_) :: n_col, naux, err_act
integer(psb_lpk_) :: mglob
integer(psb_ipk_) :: debug_level, debug_unit
type(psb_ctxt_type) :: ctxt
integer(psb_ipk_) :: np, me
integer(psb_ipk_) :: i, j, it, itx, istop_, itmax_, itrace_, nl, m, nrst
complex(psb_spk_) :: hjj
complex(psb_spk_), allocatable, target :: aux(:)
character(len=20) :: name
type(psb_itconv_type) :: stopdat
character(len=*), parameter :: methdname='GCR'
info = psb_success_
name = 'psb_cgcr'
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 (.not.allocated(b%v)) then
info = psb_err_invalid_vect_state_
call psb_errpush(info,name)
goto 9999
endif
if (.not.allocated(x%v)) then
info = psb_err_invalid_vect_state_
call psb_errpush(info,name)
goto 9999
endif
mglob = desc_a%get_global_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||, 2-norm
!
if ((istop_ < 1 ).or.(istop_ > 2 ) ) then
info=psb_err_invalid_istop_
err=info
call psb_errpush(info,name,i_err=(/istop_/))
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
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 = 10
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_istop_
err=info
call psb_errpush(info,name,i_err=(/nl/))
goto 9999
endif
naux=4*n_col
allocate(aux(naux),h(nl+1,nl+1),&
&c_scale(nl+1),c(nl+1),z(nl+1), alpha(nl+1), stat=info)
h = czero
if (info /= psb_success_) then
info=psb_err_from_subroutine_non_
call psb_errpush(info,name)
goto 9999
end if
call psb_geasb(r, desc_a,info, scratch=.true.,mold=x%v)
do i =1,nl+1
call psb_geasb(c(i), desc_a,info, scratch=.true.,mold=x%v)
call psb_geasb(z(i), desc_a,info, scratch=.true.,mold=x%v)
call psb_geasb(c_scale(i), desc_a,info, scratch=.true.,mold=x%v)
end do
itx = 0
nrst = -1
call psb_init_conv(methdname,istop_,itrace_,itmax_,a,x,b,eps,desc_a,stopdat,info)
restart: do
if (itx>= itmax_) exit restart
h = czero
it = 0
! compute r0 = b-ax0
if (info /= psb_success_) then
info=psb_err_from_subroutine_non_
call psb_errpush(info,name)
goto 9999
end if
call psb_geaxpby(cone, b, czero, r, desc_a, info)
call psb_spmm(-cone,a,x,cone,r,desc_a,info,work=aux)
if (info /= psb_success_) then
info=psb_err_from_subroutine_non_
call psb_errpush(info,name)
goto 9999
end if
if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
nrst = nrst + 1
iteration: do
itx = itx + 1
it = it + 1
j = it
!Apply preconditioner
call prec%apply(r,z(j),desc_a,info,work=aux)
call psb_spmm(cone,a,z(j),czero,c(1),desc_a,info,work=aux)
do i =1, j - 1
h(i,j) = psb_gedot(c_scale(i), c(i), desc_a, info)
call psb_geaxpby(cone, c(i), czero, c(i+1), desc_a, info)
call psb_geaxpby(-h(i,j), c_scale(i), cone, c(i+1), desc_a, info)
end do
h(j,j) = psb_norm2(c(j), desc_a, info)
hjj = cone/h(j,j)
call psb_geaxpby(hjj, c(j), czero, c_scale(j), desc_a, info)
alpha(j) = psb_gedot(c_scale(j), r, desc_a, info)
!Update residual
call psb_geaxpby(cone, r, czero, r, desc_a, info)
call psb_geaxpby(-alpha(j), c_scale(j), cone, r, desc_a, info)
if (psb_check_conv(methdname,itx,x,r,desc_a,stopdat,info)) exit restart
if (j >= irst) exit iteration
end do iteration
m = j
!Compute solution
call ctrsm('l','u','n','n',m,1,cone,h,size(h,1),alpha,size(alpha,1))
if (nrst == 0 ) then
call x%set(czero)
endif
do i=1,m
call psb_geaxpby(alpha(i), z(i), cone, x, desc_a, info)
enddo
end do restart
m = j
!Compute solution
call ctrsm('l','u','n','n',m,1,cone,h,size(h,1),alpha,size(alpha,1))
call x%set(czero)
do i=1,m
call psb_geaxpby(alpha(i), z(i), cone, x, desc_a, info)
enddo
iter = j
call psb_end_conv(methdname,itx,desc_a,stopdat,info,derr,iter)
if (present(err)) err = derr
if (info == psb_success_) call psb_gefree(r,desc_a,info)
do j = 1,m
if (info == psb_success_) call psb_gefree(z(j),desc_a,info)
if (info == psb_success_) call psb_gefree(c_scale(j),desc_a,info)
enddo
do i =1,nl+1
if (info == psb_success_) call psb_gefree(c(i),desc_a,info)
end do
if (info == psb_success_) deallocate(aux,h,c_scale,z,c,alpha,stat=info)
if (info /= psb_success_) then
info=psb_err_from_subroutine_non_
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()
return
end if
return
end subroutine psb_cgcr_vect