Date: 2024-12-02T08:57:05+00:00

Actual source code: test39.c
slepc-3.22.2 2024-12-02
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain

      6:    This file is part of SLEPc.
      7:    SLEPc is distributed under a 2-clause BSD license (see LICENSE).
      8:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      9: */

     11: static char help[] = "Tests multiple calls to EPSSolve with matrices of different local size.\n\n"
     12:   "The command line options are:\n"
     13:   "  -n <n>, where <n> = number of grid subdivisions in x dimension.\n"
     14:   "  -m <m>, where <m> = number of grid subdivisions in y dimension.\n\n";

     16: #include <slepceps.h>

     18: /*
     19:    Create 2-D Laplacian matrix
     20: */
     21: PetscErrorCode Laplacian(MPI_Comm comm,PetscInt n,PetscInt m,PetscInt shift,Mat *A)
     22: {
     23:   PetscInt       N = n*m,i,j,II,Istart,Iend,nloc;
     24:   PetscMPIInt    rank;

     26:   PetscFunctionBeginUser;
     27:   PetscCallMPI(MPI_Comm_rank(PETSC_COMM_WORLD,&rank));
     28:   nloc = PETSC_DECIDE;
     29:   PetscCall(PetscSplitOwnership(comm,&nloc,&N));
     30:   if (rank==0) nloc += shift;
     31:   else if (rank==1) nloc -= shift;

     33:   PetscCall(MatCreate(comm,A));
     34:   PetscCall(MatSetSizes(*A,nloc,nloc,N,N));
     35:   PetscCall(MatSetFromOptions(*A));
     36:   PetscCall(MatGetOwnershipRange(*A,&Istart,&Iend));
     37:   for (II=Istart;II<Iend;II++) {
     38:     i = II/n; j = II-i*n;
     39:     if (i>0) PetscCall(MatSetValue(*A,II,II-n,-1.0,INSERT_VALUES));
     40:     if (i<m-1) PetscCall(MatSetValue(*A,II,II+n,-1.0,INSERT_VALUES));
     41:     if (j>0) PetscCall(MatSetValue(*A,II,II-1,-1.0,INSERT_VALUES));
     42:     if (j<n-1) PetscCall(MatSetValue(*A,II,II+1,-1.0,INSERT_VALUES));
     43:     PetscCall(MatSetValue(*A,II,II,4.0,INSERT_VALUES));
     44:   }
     45:   PetscCall(MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY));
     46:   PetscCall(MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY));
     47:   PetscFunctionReturn(PETSC_SUCCESS);
     48: }

     50: int main(int argc,char **argv)
     51: {
     52:   Mat            A,B;
     53:   EPS            eps;
     54:   PetscInt       N,n=10,m=11,nev=3;
     55:   PetscMPIInt    size;
     56:   PetscBool      flag,terse;

     58:   PetscFunctionBeginUser;
     59:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
     60:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
     61:   PetscCheck(size>1,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"This example requires at least two processes");
     62:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     63:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
     64:   N = n*m;
     65:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n2-D Laplacian Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));

     67:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     68:                 Create 2-D Laplacian matrices
     69:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     71:   PetscCall(Laplacian(PETSC_COMM_WORLD,n,m,1,&A));
     72:   PetscCall(Laplacian(PETSC_COMM_WORLD,n,m,-1,&B));

     74:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     75:         Create the eigensolver, set options and solve the eigensystem
     76:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     78:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"First solve:\n\n"));
     79:   PetscCall(EPSCreate(PETSC_COMM_WORLD,&eps));
     80:   PetscCall(EPSSetOperators(eps,A,NULL));
     81:   PetscCall(EPSSetProblemType(eps,EPS_HEP));
     82:   PetscCall(EPSSetWhichEigenpairs(eps,EPS_SMALLEST_REAL));
     83:   PetscCall(EPSSetDimensions(eps,nev,PETSC_DETERMINE,PETSC_DETERMINE));
     84:   PetscCall(EPSSetFromOptions(eps));

     86:   PetscCall(EPSSolve(eps));

     88:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     89:                     Display solution of first solve
     90:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     92:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
     93:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
     94:   else {
     95:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
     96:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
     97:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
     98:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
     99:   }

    101:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    102:                        Solve with second matrix
    103:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

    105:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nSecond solve:\n\n"));
    106:   /* PetscCall(EPSReset(eps)); */  /* not required, will be called in EPSSetOperators() */
    107:   PetscCall(EPSSetOperators(eps,B,NULL));
    108:   PetscCall(EPSSolve(eps));

    110:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
    111:   else {
    112:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
    113:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
    114:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
    115:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
    116:   }

    118:   PetscCall(EPSDestroy(&eps));
    119:   PetscCall(MatDestroy(&A));
    120:   PetscCall(MatDestroy(&B));
    121:   PetscCall(SlepcFinalize());
    122:   return 0;
    123: }

    125: /*TEST

    127:    testset:
    128:       nsize: 2
    129:       requires: !single
    130:       output_file: output/test39_1.out
    131:       test:
    132:          suffix: 1
    133:          args: -eps_type {{krylovschur arnoldi lobpcg lapack}} -terse
    134:       test:
    135:          suffix: 1_lanczos
    136:          args: -eps_type lanczos -eps_lanczos_reorthog local -terse

    138: TEST*/