!!$
!!$
!!$ MLD2P4 version 1.0
!!$ MultiLevel Domain Decomposition Parallel Preconditioners Package
!!$ based on PSBLAS (Parallel Sparse BLAS version 2.2)
!!$
!!$ (C) Copyright 2008
!!$
!!$ Salvatore Filippone University of Rome Tor Vergata
!!$ Alfredo Buttari University of Rome Tor Vergata
!!$ Pasqua D'Ambra ICAR-CNR, Naples
!!$ Daniela di Serafino Second University of Naples
!!$
!!$ 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_dexample_ml.f90
!
! This sample program solves a linear system by using BiCGStab preconditioned by
! RAS with overlap 2 and ILU(0) on the local blocks, as explained in Section 6.1
! of the MLD2P4 User's and Reference Guide.
!
! The matrix and the rhs are read from files (if an rhs is not available, the
! unit rhs is set).
!
program mld_dexample_ml
use psb_base_mod
use mld_prec_mod
use psb_krylov_mod
use psb_util_mod
use data_input
implicit none
! input parameters
character(len=40) :: mtrx_file, rhs_file
character(len=2) :: filefmt
! sparse matrices
type(psb_dspmat_type) :: A, aux_A
! descriptor of sparse matrices
type(psb_desc_type):: desc_A
! preconditioner
type(mld_dprec_type) :: P
! right-hand side, solution and residual vectors
real(psb_dpk_), allocatable , save :: b(:), x(:), r(:), &
& x_glob(:), r_glob(:)
real(psb_dpk_), allocatable, target :: aux_b(:,:)
real(psb_dpk_), pointer :: b_glob(:)
! solver and preconditioner parameters
real(psb_dpk_) :: tol, err
integer :: itmax, iter, istop
integer :: nlev
! parallel environment parameters
integer :: ictxt, iam, np
! other variables
integer :: i,info,j,m_problem,amatsize,descsize,precsize
integer :: ierr, ircode
real(psb_dpk_) :: t1, t2, tprec, resmx, resmxp
character(len=20) :: name
integer, parameter :: iunit=12
! initialize the parallel environment
call psb_init(ictxt)
call psb_info(ictxt,iam,np)
if (iam < 0) then
! This should not happen, but just in case
call psb_exit(ictxt)
stop
endif
name='mld_dexample_ml'
if(psb_get_errstatus() /= 0) goto 9999
info=0
call psb_set_errverbosity(2)
! get parameters
call get_parms(ictxt,mtrx_file,rhs_file,filefmt,itmax,tol)
call psb_barrier(ictxt)
t1 = psb_wtime()
! read and assemble the matrix A and the right-hand side b
! using PSBLAS routines for sparse matrix / vector management
if (iam==psb_root_) then
select case(psb_toupper(filefmt))
case('MM')
! For Matrix Market we have an input file for the matrix
! and an (optional) second file for the RHS.
call mm_mat_read(aux_a,info,iunit=iunit,filename=mtrx_file)
if (info == 0) then
if (rhs_file /= 'NONE') then
call mm_vet_read(aux_b,info,iunit=iunit,filename=rhs_file)
end if
end if
case ('HB')
! For Harwell-Boeing we have a single file which may or may not
! contain an RHS.
call hb_read(aux_a,info,iunit=iunit,b=aux_b,filename=mtrx_file)
case default
info = -1
write(0,*) 'Wrong choice for fileformat ', filefmt
end select
if (info /= 0) then
write(0,*) 'Error while reading input matrix '
call psb_abort(ictxt)
end if
m_problem = aux_a%m
call psb_bcast(ictxt,m_problem)
! At this point aux_b may still be unallocated
if (psb_size(aux_b,1)==m_problem) then
! if any rhs were present, broadcast the first one
write(0,'("Ok, got an rhs ")')
b_glob =>aux_b(:,1)
else
write(*,'("Generating an rhs...")')
write(*,'(" ")')
call psb_realloc(m_problem,1,aux_b,ircode)
if (ircode /= 0) then
call psb_errpush(4000,name)
goto 9999
endif
b_glob => aux_b(:,1)
do i=1, m_problem
b_glob(i) = 1.d0
enddo
endif
call psb_bcast(ictxt,b_glob(1:m_problem))
else
call psb_bcast(ictxt,m_problem)
call psb_realloc(m_problem,1,aux_b,ircode)
if (ircode /= 0) then
call psb_errpush(4000,name)
goto 9999
endif
b_glob =>aux_b(:,1)
call psb_bcast(ictxt,b_glob(1:m_problem))
end if
call psb_barrier(ictxt)
if (iam==psb_root_) write(*,'("Partition type: block")')
call psb_matdist(aux_A, A, part_block, ictxt, &
& desc_A,b_glob,b,info)
t2 = psb_wtime() - t1
call psb_amx(ictxt, t2)
if (iam==psb_root_) then
write(*,'(" ")')
write(*,'("Time to read and partition matrix : ",es10.4)')t2
write(*,'(" ")')
end if
! set RAS with overlap 2 and ILU(0) on the local blocks
call mld_precinit(P,'AS',info)
call mld_precset(P,mld_sub_ovr_,2,info)
! build the preconditioner
t1 = psb_wtime()
call mld_precbld(A,desc_A,P,info)
tprec = psb_wtime()-t1
call psb_amx(ictxt, tprec)
if (info /= 0) then
call psb_errpush(4010,name,a_err='psb_precbld')
goto 9999
end if
! set the initial guess
call psb_geall(x,desc_A,info)
x(:) =0.0
call psb_geasb(x,desc_A,info)
! solve Ax=b with preconditioned BiCGSTAB
call psb_barrier(ictxt)
t1 = psb_wtime()
call psb_krylov('BICGSTAB',A,P,b,x,tol,desc_A,info,itmax,iter,err,istop=2)
t2 = psb_wtime() - t1
call psb_amx(ictxt,t2)
call psb_geall(r,desc_A,info)
r(:) =0.0
call psb_geasb(r,desc_A,info)
call psb_geaxpby(done,b,dzero,r,desc_A,info)
call psb_spmm(-done,A,x,done,r,desc_A,info)
call psb_genrm2s(resmx,r,desc_A,info)
call psb_geamaxs(resmxp,r,desc_A,info)
amatsize = psb_sizeof(A)
descsize = psb_sizeof(desc_A)
precsize = mld_sizeof(P)
call psb_sum(ictxt,amatsize)
call psb_sum(ictxt,descsize)
call psb_sum(ictxt,precsize)
call mld_precdescr(P,info)
if (iam==psb_root_) then
write(*,'(" ")')
write(*,'("Matrix: ",A)')mtrx_file
write(*,'("Computed solution on ",i8," processors")')np
write(*,'("Iterations to convergence : ",i6)')iter
write(*,'("Error estimate on exit : ",es10.4)')err
write(*,'("Time to build prec. : ",es10.4)')tprec
write(*,'("Time to solve system : ",es10.4)')t2
write(*,'("Time per iteration : ",es10.4)')t2/(iter)
write(*,'("Total time : ",es10.4)')t2+tprec
write(*,'("Residual 2-norm : ",es10.4)')resmx
write(*,'("Residual inf-norm : ",es10.4)')resmxp
write(*,'("Total memory occupation for A : ",i10)')amatsize
write(*,'("Total memory occupation for DESC_A : ",i10)')descsize
write(*,'("Total memory occupation for PREC : ",i10)')precsize
end if
allocate(x_glob(m_problem),r_glob(m_problem),stat=ierr)
if (ierr /= 0) then
write(0,*) 'allocation error: no data collection'
else
call psb_gather(x_glob,x,desc_A,info,root=psb_root_)
call psb_gather(r_glob,r,desc_A,info,root=psb_root_)
if (iam==psb_root_) then
write(0,'(" ")')
write(0,'("Saving x on file")')
write(20,*) 'matrix: ',mtrx_file
write(20,*) 'computed solution on ',np,' processor(s).'
write(20,*) 'iterations to convergence: ',iter
write(20,*) 'error estimate (infinity norm) on exit:', &
& ' ||r||/(||a||||x||+||b||) = ',err
write(20,*) 'max residual = ',resmx, resmxp
write(20,'(a8,4(2x,a20))') 'I','X(I)','R(I)','B(I)'
do i=1,m_problem
write(20,998) i,x_glob(i),r_glob(i),b_glob(i)
enddo
end if
end if
998 format(i8,4(2x,g20.14))
993 format(i6,4(1x,e12.6))
! deallocate the data structures
call psb_gefree(b, desc_A,info)
call psb_gefree(x, desc_A,info)
call psb_spfree(A, desc_A,info)
call mld_precfree(P,info)
call psb_cdfree(desc_A,info)
9999 continue
if(info /= 0) then
call psb_error(ictxt)
end if
call psb_exit(ictxt)
stop
contains
!
! get parameters from standard input
!
subroutine get_parms(ictxt,mtrx,rhs,filefmt,itmax,tol)
use psb_base_mod
implicit none
integer :: ictxt, itmax
real(psb_dpk_) :: tol
character(len=*) :: mtrx, rhs,filefmt
integer :: iam, np
call psb_info(ictxt,iam,np)
if (iam==psb_root_) then
! read input parameters
call read_data(mtrx,5)
call read_data(rhs,5)
call read_data(filefmt,5)
call read_data(itmax,5)
call read_data(tol,5)
end if
call psb_bcast(ictxt,mtrx)
call psb_bcast(ictxt,rhs)
call psb_bcast(ictxt,filefmt)
call psb_bcast(ictxt,itmax)
call psb_bcast(ictxt,tol)
end subroutine get_parms
end program mld_dexample_ml