! ! ! 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_cexample_1lev.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 4.1 ! of the AMG4PSBLAS 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 amg_cexample_1lev use psb_base_mod use amg_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_cspmat_type) :: A, aux_A ! descriptor of sparse matrices type(psb_desc_type):: desc_A ! preconditioner type(amg_cprec_type) :: P ! right-hand side, solution and residual vectors type(psb_c_vect_type) :: b, x, r complex(psb_spk_), allocatable , save :: x_glob(:), r_glob(:) complex(psb_spk_), allocatable, target :: aux_b(:,:) complex(psb_spk_), pointer :: b_glob(:) ! solver and preconditioner parameters real(psb_spk_) :: tol, err integer :: itmax, iter, istop integer :: nlev ! parallel environment parameters type(psb_ctxt_type) :: ctxt integer :: iam, np ! other variables integer :: i,info,j,m_problem integer(psb_epk_) :: amatsize, precsize, descsize integer :: ierr, ircode real(psb_spk_) :: 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_cexample_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,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 ! START SETTING PARAMETER ! set RAS call P%init(ctxt,'AS',info) ! set number of overlaps call P%set('SUB_OVR',2,info) ! build the preconditioner t1 = psb_wtime() call P%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 Krylov method: BiCGSTAB kmethod = 'BiCGSTAB' call psb_barrier(ctxt) t1 = psb_wtime() call psb_krylov(kmethod,A,P,b,x,tol,desc_A,info,itmax,iter,err,istop=2) t2 = psb_wtime() - t1 call psb_amx(ctxt,t2) call psb_geasb(r,desc_A,info,scratch=.true.) call psb_geaxpby(cone,b,czero,r,desc_A,info) call psb_spmm(-cone,A,x,cone,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,' 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 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,itmax,tol) implicit none type(psb_ctxt_type) :: ctxt integer :: itmax real(psb_spk_) :: 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(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,itmax) call psb_bcast(ctxt,tol) end subroutine get_parms end program amg_cexample_1lev