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amg4psblas/tests/pdegen/amg_s_pde2d.f90

611 lines
24 KiB
Fortran

!
!
! AMG4PSBLAS version 1.0
! Algebraic Multigrid Package
! based on PSBLAS (Parallel Sparse BLAS version 3.5)
!
! (C) Copyright 2020
!
! 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_s_pde2d.f90
!
! Program: amg_s_pde2d
! This sample program solves a linear system obtained by discretizing a
! PDE with Dirichlet BCs.
!
!
! The PDE is a general second order equation in 2d
!
! a1 dd(u) a2 dd(u) b1 d(u) b2 d(u)
! - ------ - ------ ----- + ------ + c u = f
! dxdx dydy dx dy
!
! with Dirichlet boundary conditions
! u = g
!
! on the unit square 0<=x,y<=1.
!
!
! Note that if b1=b2=c=0., the PDE is the Laplace equation.
!
! There are three choices available for data distribution:
! 1. A simple BLOCK distribution
! 2. A ditribution based on arbitrary assignment of indices to processes,
! typically from a graph partitioner
! 3. A 2D distribution in which the unit square is partitioned
! into rectangles, each one assigned to a process.
!
program amg_s_pde2d
use psb_base_mod
use amg_prec_mod
use psb_krylov_mod
use psb_util_mod
use data_input
use amg_s_pde2d_base_mod
use amg_s_pde2d_exp_mod
use amg_s_pde2d_box_mod
use amg_s_genpde_mod
implicit none
! input parameters
character(len=20) :: kmethd, ptype
character(len=5) :: afmt, pdecoeff
integer(psb_ipk_) :: idim
integer(psb_epk_) :: system_size
! miscellaneous
real(psb_dpk_) :: t1, t2, tprec, thier, tslv
! sparse matrix and preconditioner
type(psb_sspmat_type) :: a
type(amg_sprec_type) :: prec
! descriptor
type(psb_desc_type) :: desc_a
! dense vectors
type(psb_s_vect_type) :: x,b,r
! parallel environment
type(psb_ctxt_type) :: ctxt
integer(psb_ipk_) :: iam, np
! solver parameters
integer(psb_ipk_) :: iter, itmax,itrace, istopc, irst, nlv
integer(psb_epk_) :: amatsize, precsize, descsize
real(psb_spk_) :: err, resmx, resmxp
! Krylov solver data
type solverdata
character(len=40) :: kmethd ! Krylov solver
integer(psb_ipk_) :: istopc ! stopping criterion
integer(psb_ipk_) :: itmax ! maximum number of iterations
integer(psb_ipk_) :: itrace ! tracing
integer(psb_ipk_) :: irst ! restart
real(psb_spk_) :: eps ! stopping tolerance
end type solverdata
type(solverdata) :: s_choice
! preconditioner data
type precdata
! preconditioner type
character(len=40) :: descr ! verbose description of the prec
character(len=10) :: ptype ! preconditioner type
integer(psb_ipk_) :: outer_sweeps ! number of outer sweeps: sweeps for 1-level,
! AMG cycles for ML
! general AMG data
character(len=16) :: mlcycle ! AMG cycle type
integer(psb_ipk_) :: maxlevs ! maximum number of levels in AMG preconditioner
! AMG aggregation
character(len=16) :: aggr_prol ! aggregation type: SMOOTHED, NONSMOOTHED
character(len=16) :: par_aggr_alg ! parallel aggregation algorithm: DEC, SYMDEC
character(len=16) :: aggr_ord ! ordering for aggregation: NATURAL, DEGREE
character(len=16) :: aggr_filter ! filtering: FILTER, NO_FILTER
real(psb_spk_) :: mncrratio ! minimum aggregation ratio
real(psb_spk_), allocatable :: athresv(:) ! smoothed aggregation threshold vector
integer(psb_ipk_) :: thrvsz ! size of threshold vector
real(psb_spk_) :: athres ! smoothed aggregation threshold
integer(psb_ipk_) :: csize ! minimum size of coarsest matrix
! AMG smoother or pre-smoother; also 1-lev preconditioner
character(len=16) :: smther ! (pre-)smoother type: BJAC, AS
integer(psb_ipk_) :: jsweeps ! (pre-)smoother / 1-lev prec. sweeps
integer(psb_ipk_) :: novr ! number of overlap layers
character(len=16) :: restr ! restriction over application of AS
character(len=16) :: prol ! prolongation over application of AS
character(len=16) :: solve ! local subsolver type: ILU, MILU, ILUT,
! UMF, MUMPS, SLU, FWGS, BWGS, JAC
integer(psb_ipk_) :: fill ! fill-in for incomplete LU factorization
real(psb_spk_) :: thr ! threshold for ILUT factorization
! AMG post-smoother; ignored by 1-lev preconditioner
character(len=16) :: smther2 ! post-smoother type: BJAC, AS
integer(psb_ipk_) :: jsweeps2 ! post-smoother sweeps
integer(psb_ipk_) :: novr2 ! number of overlap layers
character(len=16) :: restr2 ! restriction over application of AS
character(len=16) :: prol2 ! prolongation over application of AS
character(len=16) :: solve2 ! local subsolver type: ILU, MILU, ILUT,
! UMF, MUMPS, SLU, FWGS, BWGS, JAC
integer(psb_ipk_) :: fill2 ! fill-in for incomplete LU factorization
real(psb_spk_) :: thr2 ! threshold for ILUT factorization
! coarsest-level solver
character(len=16) :: cmat ! coarsest matrix layout: REPL, DIST
character(len=16) :: csolve ! coarsest-lev solver: BJAC, SLUDIST (distr.
! mat.); UMF, MUMPS, SLU, ILU, ILUT, MILU
! (repl. mat.)
character(len=16) :: csbsolve ! coarsest-lev local subsolver: ILU, ILUT,
! MILU, UMF, MUMPS, SLU
integer(psb_ipk_) :: cfill ! fill-in for incomplete LU factorization
real(psb_spk_) :: cthres ! threshold for ILUT factorization
integer(psb_ipk_) :: cjswp ! sweeps for GS or JAC coarsest-lev subsolver
end type precdata
type(precdata) :: p_choice
! other variables
integer(psb_ipk_) :: info, i, k
character(len=20) :: name,ch_err
info=psb_success_
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
if(psb_get_errstatus() /= 0) goto 9999
name='amg_s_pde2d'
call psb_set_errverbosity(itwo)
!
! 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,afmt,idim,s_choice,p_choice,pdecoeff)
!
! allocate and fill in the coefficient matrix, rhs and initial guess
!
call psb_barrier(ctxt)
t1 = psb_wtime()
select case(psb_toupper(trim(pdecoeff)))
case("CONST")
call amg_gen_pde2d(ctxt,idim,a,b,x,desc_a,afmt,&
& a1,a2,b1,b2,c,g,info)
case("EXP")
call amg_gen_pde2d(ctxt,idim,a,b,x,desc_a,afmt,&
& a1_exp,a2_exp,b1_exp,b2_exp,c_exp,g_exp,info)
case("BOX")
call amg_gen_pde2d(ctxt,idim,a,b,x,desc_a,afmt,&
& a1_box,a2_box,b1_box,b2_box,c_box,g_box,info)
case default
info=psb_err_from_subroutine_
ch_err='amg_gen_pdecoeff'
call psb_errpush(info,name,a_err=ch_err)
goto 9999
end select
call psb_barrier(ctxt)
t2 = psb_wtime() - t1
if(info /= psb_success_) then
info=psb_err_from_subroutine_
ch_err='amg_gen_pde2d'
call psb_errpush(info,name,a_err=ch_err)
goto 9999
end if
if (iam == psb_root_) &
& write(psb_out_unit,'("PDE Coefficients : ",a)')pdecoeff
if (iam == psb_root_) &
& write(psb_out_unit,'("Overall matrix creation time : ",es12.5)')t2
if (iam == psb_root_) &
& write(psb_out_unit,'(" ")')
!
! initialize the preconditioner
!
call prec%init(ctxt,p_choice%ptype,info)
select case(trim(psb_toupper(p_choice%ptype)))
case ('NONE','NOPREC')
! Do nothing, keep defaults
case ('JACOBI','L1-JACOBI','GS','FWGS','FBGS')
! 1-level sweeps from "outer_sweeps"
call prec%set('smoother_sweeps', p_choice%jsweeps, info)
case ('BJAC')
call prec%set('smoother_sweeps', p_choice%jsweeps, info)
call prec%set('sub_solve', p_choice%solve, info)
call prec%set('sub_fillin', p_choice%fill, info)
call prec%set('sub_iluthrs', p_choice%thr, info)
case('AS')
call prec%set('smoother_sweeps', p_choice%jsweeps, info)
call prec%set('sub_ovr', p_choice%novr, info)
call prec%set('sub_restr', p_choice%restr, info)
call prec%set('sub_prol', p_choice%prol, info)
call prec%set('sub_solve', p_choice%solve, info)
call prec%set('sub_fillin', p_choice%fill, info)
call prec%set('sub_iluthrs', p_choice%thr, info)
case ('ML')
! multilevel preconditioner
call prec%set('ml_cycle', p_choice%mlcycle, info)
call prec%set('outer_sweeps', p_choice%outer_sweeps,info)
if (p_choice%csize>0)&
& call prec%set('min_coarse_size', p_choice%csize, info)
if (p_choice%mncrratio>1)&
& call prec%set('min_cr_ratio', p_choice%mncrratio, info)
if (p_choice%maxlevs>0)&
& call prec%set('max_levs', p_choice%maxlevs, info)
if (p_choice%athres >= dzero) &
& call prec%set('aggr_thresh', p_choice%athres, info)
if (p_choice%thrvsz>0) then
do k=1,min(p_choice%thrvsz,size(prec%precv)-1)
call prec%set('aggr_thresh', p_choice%athresv(k), info,ilev=(k+1))
end do
end if
call prec%set('aggr_prol', p_choice%aggr_prol, info)
call prec%set('par_aggr_alg', p_choice%par_aggr_alg, info)
call prec%set('aggr_ord', p_choice%aggr_ord, info)
call prec%set('aggr_filter', p_choice%aggr_filter,info)
call prec%set('smoother_type', p_choice%smther, info)
call prec%set('smoother_sweeps', p_choice%jsweeps, info)
select case (psb_toupper(p_choice%smther))
case ('GS','BWGS','FBGS','JACOBI','L1-JACOBI')
! do nothing
case default
call prec%set('sub_ovr', p_choice%novr, info)
call prec%set('sub_restr', p_choice%restr, info)
call prec%set('sub_prol', p_choice%prol, info)
call prec%set('sub_solve', p_choice%solve, info)
call prec%set('sub_fillin', p_choice%fill, info)
call prec%set('sub_iluthrs', p_choice%thr, info)
end select
if (psb_toupper(p_choice%smther2) /= 'NONE') then
call prec%set('smoother_type', p_choice%smther2, info,pos='post')
call prec%set('smoother_sweeps', p_choice%jsweeps2, info,pos='post')
select case (psb_toupper(p_choice%smther2))
case ('GS','BWGS','FBGS','JACOBI','L1-JACOBI')
! do nothing
case default
call prec%set('sub_ovr', p_choice%novr2, info,pos='post')
call prec%set('sub_restr', p_choice%restr2, info,pos='post')
call prec%set('sub_prol', p_choice%prol2, info,pos='post')
call prec%set('sub_solve', p_choice%solve2, info,pos='post')
call prec%set('sub_fillin', p_choice%fill2, info,pos='post')
call prec%set('sub_iluthrs', p_choice%thr2, info,pos='post')
end select
end if
call prec%set('coarse_solve', p_choice%csolve, info)
if (psb_toupper(p_choice%csolve) == 'BJAC') &
& call prec%set('coarse_subsolve', p_choice%csbsolve, info)
call prec%set('coarse_mat', p_choice%cmat, info)
call prec%set('coarse_fillin', p_choice%cfill, info)
call prec%set('coarse_iluthrs', p_choice%cthres, info)
call prec%set('coarse_sweeps', p_choice%cjswp, info)
end select
! build the preconditioner
call psb_barrier(ctxt)
t1 = psb_wtime()
call prec%hierarchy_build(a,desc_a,info)
thier = psb_wtime()-t1
if (info /= psb_success_) then
call psb_errpush(psb_err_from_subroutine_,name,a_err='amg_hierarchy_bld')
goto 9999
end if
call psb_barrier(ctxt)
t1 = psb_wtime()
call prec%smoothers_build(a,desc_a,info)
tprec = psb_wtime()-t1
if (info /= psb_success_) then
call psb_errpush(psb_err_from_subroutine_,name,a_err='amg_smoothers_bld')
goto 9999
end if
call psb_amx(ctxt, thier)
call psb_amx(ctxt, tprec)
if(iam == psb_root_) then
write(psb_out_unit,'(" ")')
write(psb_out_unit,'("Preconditioner: ",a)') trim(p_choice%descr)
write(psb_out_unit,'("Preconditioner time: ",es12.5)')thier+tprec
write(psb_out_unit,'(" ")')
end if
!
! iterative method parameters
!
call psb_barrier(ctxt)
t1 = psb_wtime()
call psb_krylov(s_choice%kmethd,a,prec,b,x,s_choice%eps,&
& desc_a,info,itmax=s_choice%itmax,iter=iter,err=err,itrace=s_choice%itrace,&
& istop=s_choice%istopc,irst=s_choice%irst)
call psb_barrier(ctxt)
tslv = psb_wtime() - t1
call psb_amx(ctxt,tslv)
if(info /= psb_success_) then
info=psb_err_from_subroutine_
ch_err='solver routine'
call psb_errpush(info,name,a_err=ch_err)
goto 9999
end if
call psb_barrier(ctxt)
tslv = psb_wtime() - t1
call psb_amx(ctxt,tslv)
! compute residual norms
call psb_geall(r,desc_a,info)
call r%zero()
call psb_geasb(r,desc_a,info)
call psb_geaxpby(sone,b,szero,r,desc_a,info)
call psb_spmm(-sone,a,x,sone,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 = prec%sizeof()
system_size = desc_a%get_global_rows()
call psb_sum(ctxt,amatsize)
call psb_sum(ctxt,descsize)
call psb_sum(ctxt,precsize)
call prec%descr(iout=psb_out_unit)
if (iam == psb_root_) then
write(psb_out_unit,'("Computed solution on ",i8," processors")') np
write(psb_out_unit,'("Linear system size : ",i12)') system_size
write(psb_out_unit,'("PDE Coefficients : ",a)') trim(pdecoeff)
write(psb_out_unit,'("Krylov method : ",a)') trim(s_choice%kmethd)
write(psb_out_unit,'("Preconditioner : ",a)') trim(p_choice%descr)
write(psb_out_unit,'("Iterations to convergence : ",i12)') iter
write(psb_out_unit,'("Relative error estimate on exit : ",es12.5)') err
write(psb_out_unit,'("Number of levels in hierarchy : ",i12)') prec%get_nlevs()
write(psb_out_unit,'("Time to build hierarchy : ",es12.5)') thier
write(psb_out_unit,'("Time to build smoothers : ",es12.5)') tprec
write(psb_out_unit,'("Total time for preconditioner : ",es12.5)') tprec+thier
write(psb_out_unit,'("Time to solve system : ",es12.5)') tslv
write(psb_out_unit,'("Time per iteration : ",es12.5)') tslv/iter
write(psb_out_unit,'("Total time : ",es12.5)') tslv+tprec+thier
write(psb_out_unit,'("Residual 2-norm : ",es12.5)') resmx
write(psb_out_unit,'("Residual inf-norm : ",es12.5)') resmxp
write(psb_out_unit,'("Total memory occupation for A : ",i12)') amatsize
write(psb_out_unit,'("Total memory occupation for DESC_A : ",i12)') descsize
write(psb_out_unit,'("Total memory occupation for PREC : ",i12)') precsize
write(psb_out_unit,'("Storage format for A : ",a )') a%get_fmt()
write(psb_out_unit,'("Storage format for DESC_A : ",a )') desc_a%get_fmt()
end if
!
! cleanup storage and exit
!
call psb_gefree(b,desc_a,info)
call psb_gefree(x,desc_a,info)
call psb_spfree(a,desc_a,info)
call prec%free(info)
call psb_cdfree(desc_a,info)
if(info /= psb_success_) then
info=psb_err_from_subroutine_
ch_err='free routine'
call psb_errpush(info,name,a_err=ch_err)
goto 9999
end if
call psb_exit(ctxt)
stop
9999 continue
call psb_error(ctxt)
contains
!
! get iteration parameters from standard input
!
!
! get iteration parameters from standard input
!
subroutine get_parms(ctxt,afmt,idim,solve,prec,pdecoeff)
implicit none
type(psb_ctxt_type) :: ctxt
integer(psb_ipk_) :: idim
character(len=*) :: afmt
type(solverdata) :: solve
type(precdata) :: prec
character(len=*) :: pdecoeff
integer(psb_ipk_) :: iam, nm, 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 data
!
call read_data(afmt,inp_unit) ! matrix storage format
call read_data(idim,inp_unit) ! Discretization grid size
call read_data(pdecoeff,inp_unit) ! PDE Coefficients
! Krylov solver data
call read_data(solve%kmethd,inp_unit) ! Krylov solver
call read_data(solve%istopc,inp_unit) ! stopping criterion
call read_data(solve%itmax,inp_unit) ! max num iterations
call read_data(solve%itrace,inp_unit) ! tracing
call read_data(solve%irst,inp_unit) ! restart
call read_data(solve%eps,inp_unit) ! tolerance
! preconditioner type
call read_data(prec%descr,inp_unit) ! verbose description of the prec
call read_data(prec%ptype,inp_unit) ! preconditioner type
! First smoother / 1-lev preconditioner
call read_data(prec%smther,inp_unit) ! smoother type
call read_data(prec%jsweeps,inp_unit) ! (pre-)smoother / 1-lev prec sweeps
call read_data(prec%novr,inp_unit) ! number of overlap layers
call read_data(prec%restr,inp_unit) ! restriction over application of AS
call read_data(prec%prol,inp_unit) ! prolongation over application of AS
call read_data(prec%solve,inp_unit) ! local subsolver
call read_data(prec%fill,inp_unit) ! fill-in for incomplete LU
call read_data(prec%thr,inp_unit) ! threshold for ILUT
! Second smoother/ AMG post-smoother (if NONE ignored in main)
call read_data(prec%smther2,inp_unit) ! smoother type
call read_data(prec%jsweeps2,inp_unit) ! (post-)smoother sweeps
call read_data(prec%novr2,inp_unit) ! number of overlap layers
call read_data(prec%restr2,inp_unit) ! restriction over application of AS
call read_data(prec%prol2,inp_unit) ! prolongation over application of AS
call read_data(prec%solve2,inp_unit) ! local subsolver
call read_data(prec%fill2,inp_unit) ! fill-in for incomplete LU
call read_data(prec%thr2,inp_unit) ! threshold for ILUT
! general AMG data
call read_data(prec%mlcycle,inp_unit) ! AMG cycle type
call read_data(prec%outer_sweeps,inp_unit) ! number of 1lev/outer sweeps
call read_data(prec%maxlevs,inp_unit) ! max number of levels in AMG prec
call read_data(prec%csize,inp_unit) ! min size coarsest mat
! aggregation
call read_data(prec%aggr_prol,inp_unit) ! aggregation type
call read_data(prec%par_aggr_alg,inp_unit) ! parallel aggregation alg
call read_data(prec%aggr_ord,inp_unit) ! ordering for aggregation
call read_data(prec%aggr_filter,inp_unit) ! filtering
call read_data(prec%mncrratio,inp_unit) ! minimum aggregation ratio
call read_data(prec%thrvsz,inp_unit) ! size of aggr thresh vector
if (prec%thrvsz > 0) then
call psb_realloc(prec%thrvsz,prec%athresv,info)
call read_data(prec%athresv,inp_unit) ! aggr thresh vector
else
read(inp_unit,*) ! dummy read to skip a record
end if
call read_data(prec%athres,inp_unit) ! smoothed aggr thresh
! coasest-level solver
call read_data(prec%csolve,inp_unit) ! coarsest-lev solver
call read_data(prec%csbsolve,inp_unit) ! coarsest-lev subsolver
call read_data(prec%cmat,inp_unit) ! coarsest mat layout
call read_data(prec%cfill,inp_unit) ! fill-in for incompl LU
call read_data(prec%cthres,inp_unit) ! Threshold for ILUT
call read_data(prec%cjswp,inp_unit) ! sweeps for GS/JAC subsolver
if (inp_unit /= psb_inp_unit) then
close(inp_unit)
end if
end if
call psb_bcast(ctxt,afmt)
call psb_bcast(ctxt,idim)
call psb_bcast(ctxt,pdecoeff)
call psb_bcast(ctxt,solve%kmethd)
call psb_bcast(ctxt,solve%istopc)
call psb_bcast(ctxt,solve%itmax)
call psb_bcast(ctxt,solve%itrace)
call psb_bcast(ctxt,solve%irst)
call psb_bcast(ctxt,solve%eps)
call psb_bcast(ctxt,prec%descr)
call psb_bcast(ctxt,prec%ptype)
! broadcast first (pre-)smoother / 1-lev prec data
call psb_bcast(ctxt,prec%smther)
call psb_bcast(ctxt,prec%jsweeps)
call psb_bcast(ctxt,prec%novr)
call psb_bcast(ctxt,prec%restr)
call psb_bcast(ctxt,prec%prol)
call psb_bcast(ctxt,prec%solve)
call psb_bcast(ctxt,prec%fill)
call psb_bcast(ctxt,prec%thr)
! broadcast second (post-)smoother
call psb_bcast(ctxt,prec%smther2)
call psb_bcast(ctxt,prec%jsweeps2)
call psb_bcast(ctxt,prec%novr2)
call psb_bcast(ctxt,prec%restr2)
call psb_bcast(ctxt,prec%prol2)
call psb_bcast(ctxt,prec%solve2)
call psb_bcast(ctxt,prec%fill2)
call psb_bcast(ctxt,prec%thr2)
! broadcast AMG parameters
call psb_bcast(ctxt,prec%mlcycle)
call psb_bcast(ctxt,prec%outer_sweeps)
call psb_bcast(ctxt,prec%maxlevs)
call psb_bcast(ctxt,prec%aggr_prol)
call psb_bcast(ctxt,prec%par_aggr_alg)
call psb_bcast(ctxt,prec%aggr_ord)
call psb_bcast(ctxt,prec%aggr_filter)
call psb_bcast(ctxt,prec%mncrratio)
call psb_bcast(ctxt,prec%thrvsz)
if (prec%thrvsz > 0) then
if (iam /= psb_root_) call psb_realloc(prec%thrvsz,prec%athresv,info)
call psb_bcast(ctxt,prec%athresv)
end if
call psb_bcast(ctxt,prec%athres)
call psb_bcast(ctxt,prec%csize)
call psb_bcast(ctxt,prec%cmat)
call psb_bcast(ctxt,prec%csolve)
call psb_bcast(ctxt,prec%csbsolve)
call psb_bcast(ctxt,prec%cfill)
call psb_bcast(ctxt,prec%cthres)
call psb_bcast(ctxt,prec%cjswp)
end subroutine get_parms
end program amg_s_pde2d