Date: 2023-09-05T10:18:00+00:00

Actual source code: test39.c
slepc-3.19.2 2023-09-05
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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(MatSetUp(*A));
     37:   PetscCall(MatGetOwnershipRange(*A,&Istart,&Iend));
     38:   for (II=Istart;II<Iend;II++) {
     39:     i = II/n; j = II-i*n;
     40:     if (i>0) PetscCall(MatSetValue(*A,II,II-n,-1.0,INSERT_VALUES));
     41:     if (i<m-1) PetscCall(MatSetValue(*A,II,II+n,-1.0,INSERT_VALUES));
     42:     if (j>0) PetscCall(MatSetValue(*A,II,II-1,-1.0,INSERT_VALUES));
     43:     if (j<n-1) PetscCall(MatSetValue(*A,II,II+1,-1.0,INSERT_VALUES));
     44:     PetscCall(MatSetValue(*A,II,II,4.0,INSERT_VALUES));
     45:   }
     46:   PetscCall(MatAssemblyBegin(*A,MAT_FINAL_ASSEMBLY));
     47:   PetscCall(MatAssemblyEnd(*A,MAT_FINAL_ASSEMBLY));
     48:   PetscFunctionReturn(PETSC_SUCCESS);
     49: }

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

     59:   PetscFunctionBeginUser;
     60:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
     61:   PetscCallMPI(MPI_Comm_size(PETSC_COMM_WORLD,&size));
     62:   PetscCheck(size>1,PETSC_COMM_WORLD,PETSC_ERR_WRONG_MPI_SIZE,"This example requires at least two processes");
     63:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     64:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag));
     65:   N = n*m;
     66:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\n2-D Laplacian Eigenproblem, N=%" PetscInt_FMT " (%" PetscInt_FMT "x%" PetscInt_FMT " grid)\n\n",N,n,m));

     68:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     69:                 Create 2-D Laplacian matrices
     70:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

     75:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     76:         Create the eigensolver, set options and solve the eigensystem
     77:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

     87:   PetscCall(EPSSolve(eps));

     89:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     90:                     Display solution of first solve
     91:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     93:   PetscCall(PetscOptionsHasName(NULL,NULL,"-terse",&terse));
     94:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
     95:   else {
     96:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
     97:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
     98:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
     99:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
    100:   }

    102:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
    103:                        Solve with second matrix
    104:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

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

    111:   if (terse) PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,NULL));
    112:   else {
    113:     PetscCall(PetscViewerPushFormat(PETSC_VIEWER_STDOUT_WORLD,PETSC_VIEWER_ASCII_INFO_DETAIL));
    114:     PetscCall(EPSConvergedReasonView(eps,PETSC_VIEWER_STDOUT_WORLD));
    115:     PetscCall(EPSErrorView(eps,EPS_ERROR_RELATIVE,PETSC_VIEWER_STDOUT_WORLD));
    116:     PetscCall(PetscViewerPopFormat(PETSC_VIEWER_STDOUT_WORLD));
    117:   }

    119:   PetscCall(EPSDestroy(&eps));
    120:   PetscCall(MatDestroy(&A));
    121:   PetscCall(MatDestroy(&B));
    122:   PetscCall(SlepcFinalize());
    123:   return 0;
    124: }

    126: /*TEST

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

    139: TEST*/