Date: 2022-11-02T11:47:44+00:00

Actual source code: test4.c
slepc-3.18.1 2022-11-02
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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[] = "Illustrates use of MFNSetBV().\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:   BV                 V;
     24:   PetscInt           k=8;
     25:   PetscReal          norm;
     26:   PetscScalar        t=2.0;
     27:   Vec                v,y;
     28:   PetscViewer        viewer;
     29:   PetscBool          flg;
     30:   char               filename[PETSC_MAX_PATH_LEN];
     31:   MFNConvergedReason reason;

     34:   SlepcInitialize(&argc,&argv,(char*)0,help);

     36:   PetscOptionsGetScalar(NULL,NULL,"-t",&t,NULL);
     37:   PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
     38:   PetscPrintf(PETSC_COMM_WORLD,"\nMatrix exponential y=exp(t*A)*e, loaded from file\n\n");

     40:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     41:                 Load matrix A from binary file
     42:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     44:   PetscOptionsGetString(NULL,NULL,"-file",filename,sizeof(filename),&flg);

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

     58:   /* set v = ones(n,1) */
     59:   MatCreateVecs(A,NULL,&y);
     60:   MatCreateVecs(A,NULL,&v);
     61:   VecSet(v,1.0);

     63:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     64:                         Create the BV object
     65:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     67:   BVCreate(PETSC_COMM_WORLD,&V);
     68:   PetscObjectSetName((PetscObject)V,"V");
     69:   BVSetSizesFromVec(V,v,k);
     70:   BVSetFromOptions(V);

     72:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     73:                 Create the solver and set various options
     74:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     76:   MFNCreate(PETSC_COMM_WORLD,&mfn);
     77:   MFNSetOperator(mfn,A);
     78:   MFNSetBV(mfn,V);
     79:   MFNGetFN(mfn,&f);
     80:   FNSetType(f,FNEXP);
     81:   FNSetScale(f,t,1.0);
     82:   MFNSetDimensions(mfn,k);
     83:   MFNSetFromOptions(mfn);

     85:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
     86:                       Solve the problem, y=exp(t*A)*v
     87:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */

     89:   MFNSolve(mfn,v,y);
     90:   MFNGetConvergedReason(mfn,&reason);
     92:   VecNorm(y,NORM_2,&norm);
     93:   PetscPrintf(PETSC_COMM_WORLD," Computed vector at time t=%.4g has norm %g\n\n",(double)PetscRealPart(t),(double)norm);

     95:   /*
     96:      Free work space
     97:   */
     98:   BVDestroy(&V);
     99:   MFNDestroy(&mfn);
    100:   MatDestroy(&A);
    101:   VecDestroy(&v);
    102:   VecDestroy(&y);
    103:   SlepcFinalize();
    104:   return 0;
    105: }

    107: /*TEST

    109:    test:
    110:       suffix: 1
    111:       args: -file ${SLEPC_DIR}/share/slepc/datafiles/matrices/bfw62b.petsc -k 12
    112:       requires: double !complex !defined(PETSC_USE_64BIT_INDICES)

    114:    test:
    115:       suffix: 2
    116:       args: -file ${DATAFILESPATH}/matrices/complex/qc324.petsc -k 12
    117:       requires: double complex datafilespath !defined(PETSC_USE_64BIT_INDICES)

    119: TEST*/