Actual source code: test2.c

slepc-3.7.3 2016-09-29
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  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2016, 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 SVD with different builds with a matrix loaded from a file"
 23:   " (matrices available in PETSc's distribution).\n\n";

 25: #include <slepcsvd.h>

 29: int main(int argc,char **argv)
 30: {
 31:   Mat            A;               /* operator matrix */
 32:   SVD            svd;             /* singular value problem solver context */
 33:   char           filename[PETSC_MAX_PATH_LEN];
 34:   const char     *prefix,*scalar,*ints,*floats;
 35:   PetscReal      tol=1000*PETSC_MACHINE_EPSILON;
 36:   PetscViewer    viewer;

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

 41:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 42:         Load the matrix for which the SVD must be computed
 43:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 44: #if defined(PETSC_USE_COMPLEX)
 45:   prefix = "nh";
 46:   scalar = "complex";
 47: #else
 48:   prefix = "ns";
 49:   scalar = "real";
 50: #endif
 51: #if defined(PETSC_USE_64BIT_INDICES)
 52:   ints   = "int64";
 53: #else
 54:   ints   = "int32";
 55: #endif
 56: #if defined(PETSC_USE_REAL_DOUBLE)
 57:   floats = "float64";
 58: #elif defined(PETSC_USE_REAL_SINGLE)
 59:   floats = "float32";
 60: #endif

 62:   PetscSNPrintf(filename,PETSC_MAX_PATH_LEN,"%s/share/petsc/datafiles/matrices/%s-%s-%s-%s",PETSC_DIR,prefix,scalar,ints,floats);
 63:   PetscPrintf(PETSC_COMM_WORLD,"\nReading matrix from binary file...\n\n");
 64:   PetscViewerBinaryOpen(PETSC_COMM_WORLD,filename,FILE_MODE_READ,&viewer);
 65:   MatCreate(PETSC_COMM_WORLD,&A);
 66:   MatSetFromOptions(A);
 67:   MatLoad(A,viewer);
 68:   PetscViewerDestroy(&viewer);

 70:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 71:                      Create the SVD solver
 72:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 73:   SVDCreate(PETSC_COMM_WORLD,&svd);
 74:   SVDSetOperator(svd,A);
 75:   SVDSetTolerances(svd,tol,PETSC_DEFAULT);
 76:   SVDSetFromOptions(svd);

 78:   /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 79:                 Solve the eigensystem and display solution
 80:      - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
 81:   SVDSolve(svd);
 82:   SVDErrorView(svd,SVD_ERROR_RELATIVE,NULL);
 83:   SVDDestroy(&svd);
 84:   MatDestroy(&A);
 85:   SlepcFinalize();
 86:   return ierr;
 87: }