Actual source code: test3.c

slepc-3.6.1 2015-09-03
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2015, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.

  8:    SLEPc is free software: you can redistribute it and/or modify it under  the
  9:    terms of version 3 of the GNU Lesser General Public License as published by
 10:    the Free Software Foundation.

 12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY
 13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS
 14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for
 15:    more details.

 17:    You  should have received a copy of the GNU Lesser General  Public  License
 18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 20: */

 22: static char help[] = "Test matrix exponential.\n\n";

 24: #include <slepcfn.h>

 28: int main(int argc,char **argv)
 29: {
 31:   FN             fn;
 32:   Mat            A,B;
 33:   PetscInt       i,j,n=10;
 34:   PetscReal      nrm;
 35:   PetscScalar    *As,tau=1.0,eta=1.0;
 36:   PetscViewer    viewer;
 37:   PetscBool      verbose;

 39:   SlepcInitialize(&argc,&argv,(char*)0,help);
 40:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
 41:   PetscOptionsGetScalar(NULL,"-tau",&tau,NULL);
 42:   PetscOptionsGetScalar(NULL,"-eta",&eta,NULL);
 43:   PetscOptionsHasName(NULL,"-verbose",&verbose);
 44:   PetscPrintf(PETSC_COMM_WORLD,"Matrix exponential, n=%D.\n",n);

 46:   /* Create exponential function eta*exp(tau*x) */
 47:   FNCreate(PETSC_COMM_WORLD,&fn);
 48:   FNSetType(fn,FNEXP);
 49:   FNSetScale(fn,tau,eta);

 51:   /* Set up viewer */
 52:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 53:   FNView(fn,viewer);
 54:   if (verbose) {
 55:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 56:   }

 58:   /* Create matrices */
 59:   MatCreateSeqDense(PETSC_COMM_SELF,n,n,NULL,&A);
 60:   PetscObjectSetName((PetscObject)A,"A");
 61:   MatCreateSeqDense(PETSC_COMM_SELF,n,n,NULL,&B);
 62:   PetscObjectSetName((PetscObject)B,"B");

 64:   /* Fill A with a symmetric Toeplitz matrix */
 65:   MatDenseGetArray(A,&As);
 66:   for (i=0;i<n;i++) As[i+i*n]=2.0;
 67:   for (j=1;j<3;j++) {
 68:     for (i=0;i<n-j;i++) { As[i+(i+j)*n]=1.0; As[(i+j)+i*n]=1.0; }
 69:   }
 70:   MatDenseRestoreArray(A,&As);
 71:   MatSetOption(A,MAT_HERMITIAN,PETSC_TRUE);
 72:   if (verbose) {
 73:     PetscPrintf(PETSC_COMM_WORLD,"Matrix A - - - - - - - -\n");
 74:     MatView(A,viewer);
 75:   }

 77:   /* Compute matrix exponential */
 78:   FNEvaluateFunctionMat(fn,A,B);
 79:   if (verbose) {
 80:     PetscPrintf(PETSC_COMM_WORLD,"Computed f(A) - - - - - - -\n");
 81:     MatView(B,viewer);
 82:   }
 83:   MatNorm(B,NORM_1,&nrm);
 84:   PetscPrintf(PETSC_COMM_WORLD,"The 1-norm of f(A) is %g\n",(double)nrm);

 86:   /* Repeat with non-symmetric A */
 87:   MatDenseGetArray(A,&As);
 88:   for (j=1;j<3;j++) {
 89:     for (i=0;i<n-j;i++) { As[(i+j)+i*n]=-1.0; }
 90:   }
 91:   MatDenseRestoreArray(A,&As);
 92:   MatSetOption(A,MAT_HERMITIAN,PETSC_FALSE);
 93:   if (verbose) {
 94:     PetscPrintf(PETSC_COMM_WORLD,"Matrix A - - - - - - - -\n");
 95:     MatView(A,viewer);
 96:   }

 98:   /* Compute matrix exponential */
 99:   FNEvaluateFunctionMat(fn,A,B);
100:   if (verbose) {
101:     PetscPrintf(PETSC_COMM_WORLD,"Computed f(A) - - - - - - -\n");
102:     MatView(B,viewer);
103:   }
104:   MatNorm(B,NORM_1,&nrm);
105:   PetscPrintf(PETSC_COMM_WORLD,"The 1-norm of f(A) is %g\n",(double)nrm);

107:   MatDestroy(&A);
108:   MatDestroy(&B);
109:   FNDestroy(&fn);
110:   SlepcFinalize();
111:   return 0;
112: }