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/******************************************************* |
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* |
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* Copyright (c) 2003-2008 by University of Queensland |
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* Earth Systems Science Computational Center (ESSCC) |
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* http://www.uq.edu.au/esscc |
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* |
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* Primary Business: Queensland, Australia |
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* Licensed under the Open Software License version 3.0 |
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* http://www.opensource.org/licenses/osl-3.0.php |
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* |
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*******************************************************/ |
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/**************************************************************/ |
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/* Paso: SystemMatrix: sets-up the preconditioner */ |
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/**************************************************************/ |
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/* Copyrights by ACcESS Australia 2003/04 */ |
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/* Author: gross@access.edu.au */ |
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/**************************************************************/ |
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#include "Paso.h" |
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#include "SystemMatrix.h" |
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#include "Solver.h" |
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/***********************************************************************************/ |
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/* free space */ |
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void Paso_Preconditioner_free(Paso_Solver_Preconditioner* in) { |
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if (in!=NULL) { |
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Paso_Solver_ILU_free(in->ilu); |
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Paso_Solver_RILU_free(in->rilu); |
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Paso_Solver_Jacobi_free(in->jacobi); |
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Paso_Solver_GS_free(in->gs); |
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Paso_Solver_AMG_free(in->amg); |
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MEMFREE(in); |
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} |
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} |
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/* call the iterative solver: */ |
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void Paso_Solver_setPreconditioner(Paso_SystemMatrix* A,Paso_Options* options) { |
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Paso_Solver_Preconditioner* prec=NULL; |
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if (A->solver==NULL) { |
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/* allocate structure to hold preconditioner */ |
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prec=MEMALLOC(1,Paso_Solver_Preconditioner); |
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if (Paso_checkPtr(prec)) return; |
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prec->type=UNKNOWN; |
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prec->rilu=NULL; |
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prec->ilu=NULL; |
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prec->jacobi=NULL; |
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prec->gs=NULL; |
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prec->amg=NULL; |
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A->solver=prec; |
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switch (options->preconditioner) { |
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default: |
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case PASO_JACOBI: |
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if (options->verbose) printf("Jacobi preconditioner is used.\n"); |
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prec->jacobi=Paso_Solver_getJacobi(A->mainBlock); |
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prec->type=PASO_JACOBI; |
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break; |
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case PASO_ILU0: |
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if (options->verbose) printf("ILU preconditioner is used.\n"); |
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prec->ilu=Paso_Solver_getILU(A->mainBlock,options->verbose); |
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prec->type=PASO_ILU0; |
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break; |
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case PASO_RILU: |
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if (options->verbose) printf("RILU preconditioner is used.\n"); |
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prec->rilu=Paso_Solver_getRILU(A->mainBlock,options->verbose); |
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prec->type=PASO_RILU; |
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break; |
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case PASO_GS: |
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if (options->verbose) printf("Gauss-Seidel preconditioner is used.\n"); |
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prec->gs=Paso_Solver_getGS(A->mainBlock,options->verbose); |
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prec->gs->sweeps=options->sweeps; |
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prec->type=PASO_GS; |
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break; |
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case PASO_AMG: |
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if (options->verbose) printf("AMG preconditioner is used.\n"); |
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prec->amg=Paso_Solver_getAMG(A->mainBlock,options->verbose,0,options->couplingParam); |
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prec->type=PASO_AMG; |
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break; |
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|
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} |
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if (! Paso_MPIInfo_noError(A->mpi_info ) ){ |
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Paso_Preconditioner_free(prec); |
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A->solver=NULL; |
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} |
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} |
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} |
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/* applies the preconditioner */ |
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/* has to be called within a parallel reqion */ |
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/* barrier synchronization is performed before the evaluation to make sure that the input vector is available */ |
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void Paso_Solver_solvePreconditioner(Paso_SystemMatrix* A,double* x,double* b){ |
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Paso_Solver_Preconditioner* prec=(Paso_Solver_Preconditioner*) A->solver; |
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switch (prec->type) { |
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default: |
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case PASO_JACOBI: |
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Paso_Solver_solveJacobi(prec->jacobi,x,b); |
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break; |
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case PASO_ILU0: |
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Paso_Solver_solveILU(prec->ilu,x,b); |
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break; |
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case PASO_RILU: |
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Paso_Solver_solveRILU(prec->rilu,x,b); |
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break; |
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case PASO_GS: |
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/* Gauss-Seidel preconditioner P=U^{-1}DL^{-1} is used here with sweeps paramenter. |
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We want to solve x_new=x_old+P^{-1}(b-Ax_old). So for fisrt 3 we will have the following: |
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x_0=0 |
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x_1=P^{-1}(b) |
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b_old=b |
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b_new=b_old+b |
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x_2=x_1+P^{-1}(b-Ax_1)=P^{-1}(b)+P^{-1}(b)-P^{-1}AP^{-1}(b)) |
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=P^{-1}(2b-AP^{-1}b)=P^{-1}(b_new-AP^{-1}b_old) |
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b_old=b_new |
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|
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b_new=b_old+b |
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x_3=....=P^{-1}(b_new-AP^{-1}b_old) |
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b_old=b_new |
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|
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So for n- steps we will use loop, but we always make sure that every value calculated only once! |
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*/ |
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Paso_Solver_solveGS(prec->gs,x,b); |
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if (prec->gs->sweeps>1) { |
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double *bold=MEMALLOC(prec->gs->n*prec->gs->n_block,double); |
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double *bnew=MEMALLOC(prec->gs->n*prec->gs->n_block,double); |
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dim_t i; |
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#pragma omp parallel for private(i) schedule(static) |
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for (i=0;i<prec->gs->n*prec->gs->n_block;++i) bold[i]=b[i]; |
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while(prec->gs->sweeps>1) { |
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#pragma omp parallel for private(i) schedule(static) |
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for (i=0;i<prec->gs->n*prec->gs->n_block;++i) bnew[i]=bold[i]+b[i]; |
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/* Compute the residual b=b-Ax*/ |
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Paso_SystemMatrix_MatrixVector_CSR_OFFSET0(DBLE(-1), A, x, DBLE(1), bnew); |
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/* Go round again*/ |
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Paso_Solver_solveGS(prec->gs,x,bnew); |
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#pragma omp parallel for private(i) schedule(static) |
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for (i=0;i<prec->gs->n*prec->gs->n_block;++i) bold[i]=bnew[i]; |
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prec->gs->sweeps=prec->gs->sweeps-1; |
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} |
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MEMFREE(bold); |
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MEMFREE(bnew); |
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} |
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break; |
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case PASO_AMG: |
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Paso_Solver_solveAMG(prec->amg,x,b); |
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break; |
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} |
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|
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} |
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