! ! ! 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_dexample_gpu.f90 ! ! This sample program solves a linear system obtained by discretizing a ! PDE with Dirichlet BCs. The solver is 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). ! ! ! The PDE is a general second order equation in 3d ! ! a1 dd(u) a2 dd(u) a3 dd(u) b1 d(u) b2 d(u) b3 d(u) ! - ------ - ------ - ------ + ----- + ------ + ------ + c u = f ! dxdx dydy dzdz dx dy dz ! ! with Dirichlet boundary conditions ! u = g ! ! on the unit cube 0<=x,y,z<=1. ! ! ! Note that if b1=b2=b3=c=0., the PDE is the Laplace equation. ! ! In this sample program the index space of the discretized ! computational domain is first numbered sequentially in a standard way, ! then the corresponding vector is distributed according to a BLOCK ! data distribution. ! program amg_dexample_gpu use psb_base_mod use amg_prec_mod use psb_krylov_mod use psb_util_mod use psb_gpu_mod use data_input use amg_d_pde_mod implicit none ! input parameters ! sparse matrices type(psb_dspmat_type) :: A ! sparse matrices descriptor type(psb_desc_type):: desc_A ! preconditioner type(amg_dprec_type) :: P ! right-hand side, solution and residual vectors type(psb_d_vect_type) :: x, b, r ! GPU variables type(psb_d_hlg_sparse_mat) :: agmold type(psb_d_vect_gpu) :: vgmold type(psb_i_vect_gpu) :: igmold ! 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 integer(psb_epk_) :: amatsize, precsize, descsize integer(psb_epk_) :: system_size integer :: idim, ierr, ircode real(psb_dpk_) :: resmx, resmxp real(psb_dpk_) :: t1, t2, tprec character(len=5) :: afmt='CSR' character(len=20) :: name, kmethod ! initialize the parallel environment call psb_init(ctxt) call psb_info(ctxt,iam,np) ! ! BEWARE: if you have NGPUS per node, the default is to ! attach to mod(IAM,NGPUS) ! call psb_gpu_init(ictxt) if (iam < 0) then ! This should not happen, but just in case call psb_exit(ctxt) stop endif name='amg_dexample_gpu' 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 write(*,*) 'Process ',iam,' running on device: ', psb_cuda_getDevice(),' out of', psb_cuda_getDeviceCount() write(*,*) 'Process ',iam,' device ', psb_cuda_getDevice(),' is a: ', trim(psb_gpu_DeviceName()) ! get parameters call get_parms(ctxt,choice,idim,itmax,tol) ! allocate and fill in the coefficient matrix, rhs and initial guess call psb_barrier(ctxt) t1 = psb_wtime() call amg_gen_pde3d(ctxt,idim,a,b,x,desc_a,afmt,& & a1,a2,a3,b1,b2,b3,c,g,info) call psb_barrier(ctxt) t2 = psb_wtime() - t1 if(info /= psb_success_) then info=psb_err_from_subroutine_ call psb_errpush(info,name) goto 9999 end if if (iam == psb_root_) write(*,'("Overall matrix creation time : ",es12.5)')t2 if (iam == psb_root_) write(*,'(" ")') select case(choice) case(1) ! initialize a V-cycle preconditioner with 4 Jacobi sweep ! and 8 Jacobi sweeps as coarsest-level solver call P%init(ctxt,'ML',info) call P%set('SMOOTHER_TYPE','JACOBI',info) call P%set('SMOOTHER_SWEEPS',4,info) call P%set('COARSE_SOLVE','JACOBI',info) call P%set('COARSE_SWEEPS',8,info) kmethod = 'CG' case(2) ! initialize a V-cycle preconditioner based on the coupled aggregation relying on matching, ! with maximum size of aggregates equal to 8 and smoothed prolongators, ! Block-Jacobi smoother using approximate inverse INVK and ! and 4 sweeps of INVK on he coarsest level 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('SUB_SOLVE','INVK',info) call P%set('COARSE_SOLVE','INVK',info) call P%set('COARSE_MAT','DIST',info) kmethod = 'CG' end select 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, amold=agmold, vmold=vgmold, imold=igmold) 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 solver parameters and the initial guess call psb_geall(x,desc_A,info) call x%zero() call psb_geasb(x,desc_A,info) ! Convert A, DESC_A,X,B to a GPU-enabled format call desc_a%cnv(mold=igmold) call a%cscnv(info,mold=agmold) call psb_geasb(x,desc_a,info,mold=vgmold) call psb_geasb(b,desc_a,info,mold=vgmold) ! solve Ax=b with preconditioned Krylov method call psb_barrier(ctxt) call prec%allocate_wrk(info) 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 prec%deallocate_wrk(info) call psb_geall(r,desc_A,info) call r%zero() 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) resmx = psb_genrm2(r,desc_A,info) resmxp = psb_geamax(r,desc_A,info) amatsize = a%sizeof() descsize = desc_a%sizeof() precsize = p%sizeof() system_size = desc_a%get_global_rows() 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 from PDE example")') write(*,'("Computed solution on ",i8," processors")')np write(*,'("Linear system size : ",i12)') system_size 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_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_gpu_exit() call psb_exit(ctxt) stop 9999 continue call psb_error(ctxt) contains ! ! get parameters from standard input ! subroutine get_parms(ctxt,choice,idim,itmax,tol) implicit none type(psb_ctxt_type) :: ctxt integer :: choice, idim, itmax real(psb_dpk_) :: tol 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(choice,inp_unit) call read_data(idim,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,choice) call psb_bcast(ctxt,idim) call psb_bcast(ctxt,itmax) call psb_bcast(ctxt,tol) end subroutine get_parms end program amg_dexample_gpu