Date: 2023-09-05T10:18:12+00:00

Actual source code: test1.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[] = "Computes exp(t*A)*v for a matrix loaded from file.\n\n"
     12:   "The command line options are:\n"
     13:   "  -t <sval>, where <sval> = scalar value that multiplies the argument.\n"
     14:   "  -file <filename>, where <filename> = matrix file in PETSc binary form.\n\n";

     16: #include <slepcmfn.h>

     18: int main(int argc,char **argv)
     19: {
     20:   Mat                A;           /* problem matrix */
     21:   MFN                mfn;
     22:   FN                 f;
     23:   PetscReal          norm;
     24:   PetscScalar        t=2.0;
     25:   Vec                v,y;
     26:   PetscViewer        viewer;
     27:   PetscBool          flg;
     28:   char               filename[PETSC_MAX_PATH_LEN];
     29:   MFNConvergedReason reason;

     31:   PetscFunctionBeginUser;
     32:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));

     34:   PetscCall(PetscOptionsGetScalar(NULL,NULL,"-t",&t,NULL));
     35:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"\nMatrix exponential y=exp(t*A)*e, loaded from file\n\n"));

     37:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     38:                 Load matrix A from binary file
     39:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     41:   PetscCall(PetscOptionsGetString(NULL,NULL,"-file",filename,sizeof(filename),&flg));
     42:   PetscCheck(flg,PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"Must indicate a file name with the -file option");

     44: #if defined(PETSC_USE_COMPLEX)
     45:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading COMPLEX matrix from a binary file...\n"));
     46: #else
     47:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Reading REAL matrix from a binary file...\n"));
     48: #endif
     49:   PetscCall(PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer));
     50:   PetscCall(MatCreate(PETSC_COMM_WORLD,&A));
     51:   PetscCall(MatSetFromOptions(A));
     52:   PetscCall(MatLoad(A,viewer));
     53:   PetscCall(PetscViewerDestroy(&viewer));

     55:   /* set v = ones(n,1) */
     56:   PetscCall(MatCreateVecs(A,NULL,&y));
     57:   PetscCall(MatCreateVecs(A,NULL,&v));
     58:   PetscCall(VecSet(v,1.0));

     60:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     61:                 Create the solver and set various options
     62:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     64:   PetscCall(MFNCreate(PETSC_COMM_WORLD,&mfn));
     65:   PetscCall(MFNSetOperator(mfn,A));
     66:   PetscCall(MFNGetFN(mfn,&f));
     67:   PetscCall(FNSetType(f,FNEXP));
     68:   PetscCall(FNSetScale(f,t,1.0));
     69:   PetscCall(MFNSetFromOptions(mfn));

     71:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     72:                       Solve the problem, y=exp(t*A)*v
     73:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     75:   PetscCall(MFNSolve(mfn,v,y));
     76:   PetscCall(MFNGetConvergedReason(mfn,&reason));
     77:   PetscCheck(reason>=0,PETSC_COMM_WORLD,PETSC_ERR_CONV_FAILED,"Solver did not converge");
     78:   PetscCall(VecNorm(y,NORM_2,&norm));
     79:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," Computed vector at time t=%.4g has norm %g\n",(double)PetscRealPart(t),(double)norm));

     81:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     82:                       Solve the problem, y=exp(t*A^T)*v
     83:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     85:   PetscCall(MFNSolveTranspose(mfn,v,y));
     86:   PetscCall(MFNGetConvergedReason(mfn,&reason));
     87:   PetscCheck(reason>=0,PETSC_COMM_WORLD,PETSC_ERR_CONV_FAILED,"Solver did not converge");
     88:   PetscCall(VecNorm(y,NORM_2,&norm));
     89:   PetscCall(PetscPrintf(PETSC_COMM_WORLD," With transpose: computed vector has norm %g\n\n",(double)norm));

     91:   /*
     92:      Free work space
     93:   */
     94:   PetscCall(MFNDestroy(&mfn));
     95:   PetscCall(MatDestroy(&A));
     96:   PetscCall(VecDestroy(&v));
     97:   PetscCall(VecDestroy(&y));
     98:   PetscCall(SlepcFinalize());
     99:   return 0;
    100: }

    102: /*TEST

    104:    testset:
    105:       args: -file ${DATAFILESPATH}/matrices/real/bfw782a.petsc -mfn_type {{krylov expokit}} -t 0.05
    106:       requires: double !complex datafilespath !defined(PETSC_USE_64BIT_INDICES)
    107:       output_file: output/test1_1.out
    108:       test:
    109:          suffix: 1
    110:       test:
    111:          suffix: 1_cuda
    112:          args: -mat_type aijcusparse
    113:          requires: cuda

    115:    testset:
    116:       args: -file ${DATAFILESPATH}/matrices/complex/qc324.petsc -mfn_type {{krylov expokit}}
    117:       requires: double complex datafilespath !defined(PETSC_USE_64BIT_INDICES)
    118:       output_file: output/test1_2.out
    119:       test:
    120:          suffix: 2
    121:       test:
    122:          suffix: 2_cuda
    123:          args: -mat_type aijcusparse
    124:          requires: cuda

    126: TEST*/