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310 lines
9.0 KiB
Fortran
310 lines
9.0 KiB
Fortran
!!$
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!!$
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!!$ MLD2P4 version 1.0
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!!$ MultiLevel Domain Decomposition Parallel Preconditioners Package
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!!$ based on PSBLAS (Parallel Sparse BLAS version 2.2)
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!!$
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!!$ (C) Copyright 2008
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!!$
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!!$ Salvatore Filippone University of Rome Tor Vergata
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!!$ Alfredo Buttari University of Rome Tor Vergata
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!!$ Pasqua D'Ambra ICAR-CNR, Naples
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!!$ Daniela di Serafino Second University of Naples
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!!$
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!!$ Redistribution and use in source and binary forms, with or without
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!!$ modification, are permitted provided that the following conditions
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!!$ are met:
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!!$ 1. Redistributions of source code must retain the above copyright
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!!$ notice, this list of conditions and the following disclaimer.
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!!$ 2. Redistributions in binary form must reproduce the above copyright
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!!$ notice, this list of conditions, and the following disclaimer in the
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!!$ documentation and/or other materials provided with the distribution.
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!!$ 3. The name of the MLD2P4 group or the names of its contributors may
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!!$ not be used to endorse or promote products derived from this
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!!$ software without specific written permission.
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!!$
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!!$ THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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!!$ ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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!!$ TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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!!$ PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE MLD2P4 GROUP OR ITS CONTRIBUTORS
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!!$ BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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!!$ CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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!!$ SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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!!$ INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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!!$ CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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!!$ ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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!!$ POSSIBILITY OF SUCH DAMAGE.
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!!$
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!!$
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! File: mld_dexample_ml.f90
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!
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! This sample program solves a linear system by using BiCGStab preconditioned by
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! RAS with overlap 2 and ILU(0) on the local blocks, as explained in Section 6.1
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! of the MLD2P4 User's and Reference Guide.
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!
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! The matrix and the rhs are read from files (if an rhs is not available, the
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! unit rhs is set).
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!
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program mld_dexample_ml
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use psb_base_mod
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use mld_prec_mod
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use psb_krylov_mod
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use psb_util_mod
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use data_input
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implicit none
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! input parameters
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character(len=40) :: mtrx_file, rhs_file
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! sparse matrices
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type(psb_dspmat_type) :: A, aux_A
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! descriptor of sparse matrices
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type(psb_desc_type):: desc_A
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! preconditioner
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type(mld_dprec_type) :: P
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! right-hand side, solution and residual vectors
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real(psb_dpk_), allocatable , save :: b(:), x(:), r(:), &
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& x_glob(:), r_glob(:)
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real(psb_dpk_), allocatable, target :: aux_b(:,:)
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real(psb_dpk_), pointer :: b_glob(:)
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! solver and preconditioner parameters
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real(psb_dpk_) :: tol, err
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integer :: itmax, iter, istop
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integer :: nlev
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! parallel environment parameters
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integer :: ictxt, iam, np
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! other variables
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integer :: i,info,j,m_problem,amatsize,descsize,precsize
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integer :: ierr, ircode
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real(psb_dpk_) :: t1, t2, tprec, resmx, resmxp
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character(len=20) :: name
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! initialize the parallel environment
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call psb_init(ictxt)
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call psb_info(ictxt,iam,np)
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if (iam < 0) then
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! This should not happen, but just in case
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call psb_exit(ictxt)
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stop
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endif
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name='mld_dexample_ml'
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if(psb_get_errstatus() /= 0) goto 9999
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info=0
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call psb_set_errverbosity(2)
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! get parameters
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call get_parms(ictxt,mtrx_file,rhs_file,itmax,tol)
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call psb_barrier(ictxt)
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t1 = psb_wtime()
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! read and assemble the matrix A and the right-hand side b
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! using PSBLAS routines for sparse matrix / vector management
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if (iam==psb_root_) then
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call read_mat(mtrx_file, aux_A, ictxt)
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m_problem = aux_A%m
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call psb_bcast(ictxt,m_problem)
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if(rhs_file /= 'NONE') then
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! reading an rhs
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call read_rhs(rhs_file,aux_b,ictxt)
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end if
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if (psb_size(aux_b,1)==m_problem) then
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! if any rhs were present, broadcast the first one
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write(0,'("Ok, got an rhs ")')
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b_glob =>aux_b(:,1)
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else
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write(*,'("Generating an rhs...")')
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write(*,'(" ")')
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call psb_realloc(m_problem,1,aux_b,ircode)
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if (ircode /= 0) then
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call psb_errpush(4000,name)
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goto 9999
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endif
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b_glob => aux_b(:,1)
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do i=1, m_problem
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b_glob(i) = 1.d0
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enddo
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endif
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call psb_bcast(ictxt,b_glob(1:m_problem))
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else
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call psb_bcast(ictxt,m_problem)
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call psb_realloc(m_problem,1,aux_b,ircode)
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if (ircode /= 0) then
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call psb_errpush(4000,name)
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goto 9999
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endif
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b_glob =>aux_b(:,1)
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call psb_bcast(ictxt,b_glob(1:m_problem))
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end if
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call psb_barrier(ictxt)
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if (iam==psb_root_) write(*,'("Partition type: block")')
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call psb_matdist(aux_A, A, part_block, ictxt, &
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& desc_A,b_glob,b,info)
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t2 = psb_wtime() - t1
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call psb_amx(ictxt, t2)
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if (iam==psb_root_) then
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write(*,'(" ")')
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write(*,'("Time to read and partition matrix : ",es10.4)')t2
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write(*,'(" ")')
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end if
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! set RAS with overlap 2 and ILU(0) on the local blocks
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call mld_precinit(P,'AS',info)
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call mld_precset(P,mld_sub_ovr_,2,info)
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! build the preconditioner
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t1 = psb_wtime()
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call mld_precbld(A,desc_A,P,info)
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tprec = psb_wtime()-t1
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call psb_amx(ictxt, tprec)
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if (info /= 0) then
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call psb_errpush(4010,name,a_err='psb_precbld')
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goto 9999
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end if
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! set the initial guess
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call psb_geall(x,desc_A,info)
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x(:) =0.0
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call psb_geasb(x,desc_A,info)
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! solve Ax=b with preconditioned BiCGSTAB
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call psb_barrier(ictxt)
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t1 = psb_wtime()
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call psb_krylov('BICGSTAB',A,P,b,x,tol,desc_A,info,itmax,iter,err,istop=2)
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t2 = psb_wtime() - t1
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call psb_amx(ictxt,t2)
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call psb_geall(r,desc_A,info)
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r(:) =0.0
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call psb_geasb(r,desc_A,info)
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call psb_geaxpby(done,b,dzero,r,desc_A,info)
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call psb_spmm(-done,A,x,done,r,desc_A,info)
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call psb_genrm2s(resmx,r,desc_A,info)
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call psb_geamaxs(resmxp,r,desc_A,info)
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amatsize = psb_sizeof(A)
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descsize = psb_sizeof(desc_A)
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precsize = mld_sizeof(P)
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call psb_sum(ictxt,amatsize)
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call psb_sum(ictxt,descsize)
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call psb_sum(ictxt,precsize)
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call mld_precdescr(P,info)
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if (iam==psb_root_) then
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write(*,'(" ")')
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write(*,'("Matrix: ",A)')mtrx_file
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write(*,'("Computed solution on ",i8," processors")')np
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write(*,'("Iterations to convergence : ",i6)')iter
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write(*,'("Error estimate on exit : ",es10.4)')err
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write(*,'("Time to build prec. : ",es10.4)')tprec
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write(*,'("Time to solve system : ",es10.4)')t2
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write(*,'("Time per iteration : ",es10.4)')t2/(iter)
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write(*,'("Total time : ",es10.4)')t2+tprec
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write(*,'("Residual 2-norm : ",es10.4)')resmx
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write(*,'("Residual inf-norm : ",es10.4)')resmxp
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write(*,'("Total memory occupation for A : ",i10)')amatsize
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write(*,'("Total memory occupation for DESC_A : ",i10)')descsize
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write(*,'("Total memory occupation for PREC : ",i10)')precsize
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end if
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allocate(x_glob(m_problem),r_glob(m_problem),stat=ierr)
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if (ierr /= 0) then
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write(0,*) 'allocation error: no data collection'
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else
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call psb_gather(x_glob,x,desc_A,info,root=psb_root_)
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call psb_gather(r_glob,r,desc_A,info,root=psb_root_)
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if (iam==psb_root_) then
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write(0,'(" ")')
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write(0,'("Saving x on file")')
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write(20,*) 'matrix: ',mtrx_file
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write(20,*) 'computed solution on ',np,' processor(s).'
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write(20,*) 'iterations to convergence: ',iter
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write(20,*) 'error estimate (infinity norm) on exit:', &
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& ' ||r||/(||a||||x||+||b||) = ',err
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write(20,*) 'max residual = ',resmx, resmxp
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write(20,'(a8,4(2x,a20))') 'I','X(I)','R(I)','B(I)'
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do i=1,m_problem
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write(20,998) i,x_glob(i),r_glob(i),b_glob(i)
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enddo
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end if
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end if
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998 format(i8,4(2x,g20.14))
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993 format(i6,4(1x,e12.6))
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! deallocate the data structures
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call psb_gefree(b, desc_A,info)
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call psb_gefree(x, desc_A,info)
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call psb_spfree(A, desc_A,info)
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call mld_precfree(P,info)
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call psb_cdfree(desc_A,info)
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9999 continue
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if(info /= 0) then
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call psb_error(ictxt)
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end if
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call psb_exit(ictxt)
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stop
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contains
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!
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! get parameters from standard input
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!
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subroutine get_parms(ictxt,mtrx,rhs,itmax,tol)
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use psb_base_mod
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implicit none
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integer :: ictxt, itmax
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real(psb_dpk_) :: tol
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character(len=*) :: mtrx, rhs
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integer :: iam, np
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call psb_info(ictxt,iam,np)
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if (iam==psb_root_) then
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! read input parameters
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call read_data(mtrx,5)
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call read_data(rhs,5)
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call read_data(itmax,5)
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call read_data(tol,5)
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end if
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call psb_bcast(ictxt,mtrx)
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call psb_bcast(ictxt,rhs)
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call psb_bcast(ictxt,itmax)
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call psb_bcast(ictxt,tol)
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end subroutine get_parms
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end program mld_dexample_ml
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