Actual source code: test4.c

slepc-3.13.3 2020-06-14
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2020, 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:   PetscErrorCode     ierr;
 29:   PetscViewer        viewer;
 30:   PetscBool          flg;
 31:   char               filename[PETSC_MAX_PATH_LEN];
 32:   MFNConvergedReason reason;

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

 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,PETSC_MAX_PATH_LEN,&flg);
 45:   if (!flg) SETERRQ(PETSC_COMM_WORLD,1,"Must indicate a file name with the -file option");

 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);
 91:   if (reason<0) SETERRQ(PETSC_COMM_WORLD,1,"Solver did not converge");
 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 ierr;
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 !define(PETSC_USE_64BIT_INDICES)

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

119: TEST*/