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amg4psblas/samples/simple/fileread/amg_zexample_ml.f90

402 lines
13 KiB
Fortran

!
!
! AMG4PSBLAS version 1.0
! Algebraic Multigrid Package
! based on PSBLAS (Parallel Sparse BLAS version 3.7)
!
! (C) Copyright 2021
!
! Salvatore Filippone
! Pasqua D'Ambra
! Fabio Durastante
!
! 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 AMG4PSBLAS 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 AMG4PSBLAS 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: amg_zexample_ml.f90
!
! This sample program solves a linear system by using CG coupled with
! one of the following multi-level preconditioner, as explained in Section 4.1
! of the AMG4PSBLAS User's and Reference Guide:
!
! - choice = 1, the default multi-level preconditioner solver, i.e.,
! V-cycle with decoupled smoothed aggregation, 1 hybrid forward/backward
! GS sweep as pre/post-smoother and UMFPACK as coarsest-level
! solver (Sec. 4.1, Listing 1)
!
! - choice = 2, a V-cycle preconditioner with 1 block-Jacobi sweep
! (with ILU(0) on the blocks) as pre- and post-smoother, and 8 block-Jacobi
! sweeps (with ILU(0) on the blocks) as coarsest-level solver (Sec. 4.1, Listing 2)
!
! - choice = 3, W-cycle preconditioner based on the coupled aggregation relying on matching,
! with maximum size of aggregates equal to 8 and smoothed prolongators,
! 2 hybrid forward/backward GS sweeps as pre/post-smoother, a distributed coarsest
! matrix, and preconditioned Flexible Conjugate Gradient as coarsest-level solver
! (Sec. 4.1, Listing 3)
!
! The matrix and the rhs are read from files (if an rhs is not available, the
! unit rhs is set).
!
program amg_zexample_ml
use psb_base_mod
use amg_prec_mod
use psb_krylov_mod
use psb_util_mod
use data_input
implicit none
! input file parameters
character(len=40) :: mtrx_file, rhs_file
character(len=2) :: filefmt
! sparse matrices
type(psb_zspmat_type) :: A, aux_A
! descriptor of sparse matrices
type(psb_desc_type):: desc_A
! preconditioner
type(amg_zprec_type) :: P
! right-hand side, solution and residual vectors
type(psb_z_vect_type) :: b, x, r
complex(psb_dpk_), allocatable , save :: x_glob(:), r_glob(:)
complex(psb_dpk_), allocatable, target :: aux_b(:,:)
complex(psb_dpk_), pointer :: b_glob(:)
! solver and preconditioner parameters
real(psb_dpk_) :: tol, err
integer :: itmax, iter, istop
integer :: nlev
! parallel environment parameters
type(psb_ctxt_type) :: ctxt
integer :: iam, np
! other variables
integer :: choice
integer :: i,info,j,m_problem
integer(psb_epk_) :: amatsize, precsize, descsize
integer :: ierr, ircode
real(psb_dpk_) :: resmx, resmxp
real(psb_dpk_) :: t1, t2, tprec
character(len=20) :: name, kmethod
integer, parameter :: iunit=12
! initialize the parallel environment
call psb_init(ctxt)
call psb_info(ctxt,iam,np)
if (iam < 0) then
! This should not happen, but just in case
call psb_exit(ctxt)
stop
endif
name='amg_zexample_ml'
if(psb_get_errstatus() /= 0) goto 9999
info=psb_success_
call psb_set_errverbosity(2)
!
! Hello world
!
if (iam == psb_root_) then
write(*,*) 'Welcome to AMG4PSBLAS version: ',amg_version_string_
write(*,*) 'This is the ',trim(name),' sample program'
end if
! get parameters
call get_parms(ctxt,mtrx_file,rhs_file,filefmt,choice,itmax,tol)
call psb_barrier(ctxt)
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 == psb_success_) then
if (rhs_file /= 'NONE') then
call mm_array_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 /= psb_success_) then
write(0,*) 'Error while reading input matrix '
call psb_abort(ctxt)
end if
m_problem = aux_a%get_nrows()
call psb_bcast(ctxt,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(psb_err_alloc_dealloc_,name)
goto 9999
endif
b_glob => aux_b(:,1)
do i=1, m_problem
b_glob(i) = 1.d0
enddo
endif
else
call psb_bcast(ctxt,m_problem)
end if
call psb_barrier(ctxt)
if (iam == psb_root_) write(*,'("Partition type: block")')
call psb_matdist(aux_A, A, ctxt, desc_A,info,parts=part_block)
call psb_scatter(b_glob,b,desc_a,info,root=psb_root_)
t2 = psb_wtime() - t1
call psb_amx(ctxt, t2)
if (iam == psb_root_) then
write(*,'(" ")')
write(*,'("Time to read and partition matrix : ",es12.5)')t2
write(*,'(" ")')
end if
select case(choice)
case(1)
! initialize the default multi-level preconditioner, i.e. V-cycle
! with decoupled smoothed aggregation, 1 hybrid forward/backward
! GS sweep as pre/post-smoother and UMFPACK as coarsest-level
! solver
call P%init(ctxt,'ML',info)
kmethod = 'CG'
case(2)
! initialize a V-cycle preconditioner with 1 block-Jacobi sweep (with
! ILU(0) on the blocks) as pre- and post-smoother, and 8 block-Jacobi
! sweeps (with ILU(0) on the blocks) as coarsest-level solver
call P%init(ctxt,'ML',info)
call P%set('SMOOTHER_TYPE','BJAC',info)
call P%set('COARSE_SOLVE','BJAC',info)
call P%set('COARSE_SWEEPS',8,info)
kmethod = 'CG'
case(3)
! initialize a W-cycle preconditioner based on the coupled aggregation relying on matching,
! with maximum size of aggregates equal to 8 and smoothed prolongators,
! 2 hybrid forward/backward GS sweeps as pre/post-smoother, a distributed coarsest
! matrix, and preconditioned Flexible Conjugate Gradient as coarsest-level solver
call P%init(ctxt,'ML',info)
call P%set('PAR_AGGR_ALG','COUPLED',info)
call P%set('AGGR_TYPE','MATCHBOXP',info)
call P%set('AGGR_SIZE',8,info)
call P%set('ML_CYCLE','WCYCLE',info)
call P%set('SMOOTHER_SWEEPS',2,info)
call P%set('COARSE_SOLVE','KRM',info)
kmethod = 'CG'
end select
! build the preconditioner
call psb_barrier(ctxt)
t1 = psb_wtime()
! build the preconditioner
call P%hierarchy_build(A,desc_A,info)
call P%smoothers_build(A,desc_A,info)
tprec = psb_wtime()-t1
call psb_amx(ctxt, tprec)
if (info /= psb_success_) then
call psb_errpush(psb_err_from_subroutine_,name,a_err='amg_precbld')
goto 9999
end if
! set the initial guess
call psb_geall(x,desc_A,info)
call x%zero()
call psb_geasb(x,desc_A,info)
! solve Ax=b with preconditioned CG
call psb_barrier(ctxt)
t1 = psb_wtime()
call psb_krylov(kmethod,A,P,b,x,tol,desc_A,info,itmax,iter,err,itrace=1,istop=2)
t2 = psb_wtime() - t1
call psb_amx(ctxt,t2)
call psb_geasb(r,desc_A,info,scratch=.true.)
call psb_geaxpby(zone,b,zzero,r,desc_A,info)
call psb_spmm(-zone,A,x,zone,r,desc_A,info)
resmx = psb_genrm2(r,desc_A,info)
resmxp = psb_geamax(r,desc_A,info)
amatsize = a%sizeof()
descsize = desc_a%sizeof()
precsize = p%sizeof()
call psb_sum(ctxt,amatsize)
call psb_sum(ctxt,descsize)
call psb_sum(ctxt,precsize)
call P%descr(info)
if (iam == psb_root_) then
write(*,'(" ")')
write(*,'("Matrix: ",A)')mtrx_file
write(*,'("Computed solution on ",i8," processors")')np
write(*,'("Krylov method : ",a)') kmethod
write(*,'("Iterations to convergence : ",i6)')iter
write(*,'("Error estimate on exit : ",es12.5)')err
write(*,'("Time to build prec. : ",es12.5)')tprec
write(*,'("Time to solve system : ",es12.5)')t2
write(*,'("Time per iteration : ",es12.5)')t2/(iter)
write(*,'("Total time : ",es12.5)')t2+tprec
write(*,'("Residual 2-norm : ",es12.5)')resmx
write(*,'("Residual inf-norm : ",es12.5)')resmxp
write(*,'("Total memory occupation for A : ",i12)')amatsize
write(*,'("Total memory occupation for DESC_A : ",i12)')descsize
write(*,'("Total memory occupation for PREC : ",i12)')precsize
end if
call psb_gather(x_glob,x,desc_a,info,root=psb_root_)
if (info == psb_success_) &
& call psb_gather(r_glob,r,desc_a,info,root=psb_root_)
if (info /= psb_success_) goto 9999
if (iam == psb_root_) then
write(0,'(" ")')
write(0,'("Saving x on file")')
write(20,*) 'matrix: ',mtrx_file
write(20,*) 'computed solution on ',np,' processors.'
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
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 P%free(info)
call psb_cdfree(desc_A,info)
call psb_exit(ctxt)
stop
9999 continue
call psb_error(ctxt)
contains
!
! get parameters from standard input
!
subroutine get_parms(ctxt,mtrx,rhs,filefmt,choice,itmax,tol)
implicit none
type(psb_ctxt_type) :: ctxt
integer :: choice, itmax
real(psb_dpk_) :: tol
character(len=*) :: mtrx, rhs,filefmt
integer :: iam, np, inp_unit
character(len=1024) :: filename
call psb_info(ctxt,iam,np)
if (iam == psb_root_) then
if (command_argument_count()>0) then
call get_command_argument(1,filename)
inp_unit = 30
open(inp_unit,file=filename,action='read',iostat=info)
if (info /= 0) then
write(psb_err_unit,*) 'Could not open file ',filename,' for input'
call psb_abort(ctxt)
stop
else
write(psb_err_unit,*) 'Opened file ',trim(filename),' for input'
end if
else
inp_unit=psb_inp_unit
end if
! read input parameters
call read_data(mtrx,inp_unit)
call read_data(rhs,inp_unit)
call read_data(filefmt,inp_unit)
call read_data(choice,inp_unit)
call read_data(itmax,inp_unit)
call read_data(tol,inp_unit)
if (inp_unit /= psb_inp_unit) then
close(inp_unit)
end if
end if
call psb_bcast(ctxt,mtrx)
call psb_bcast(ctxt,rhs)
call psb_bcast(ctxt,filefmt)
call psb_bcast(ctxt,choice)
call psb_bcast(ctxt,itmax)
call psb_bcast(ctxt,tol)
end subroutine get_parms
end program amg_zexample_ml