Actual source code: test2.c

  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2013, 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 DSHEP.\n\n";

 24: #include <slepcds.h>
 25: #include <slepc-private/dsimpl.h>    /* for the definition of SlepcCompare* */

 29: int main(int argc,char **argv)
 30: {
 32:   DS             ds;
 33:   PetscScalar    *A,*eig;
 34:   PetscInt       i,j,n=10,ld;
 35:   PetscViewer    viewer;
 36:   PetscBool      verbose,extrarow;

 38:   SlepcInitialize(&argc,&argv,(char*)0,help);
 39:   PetscOptionsGetInt(NULL,"-n",&n,NULL);
 40:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type HEP - dimension %D.\n",n);
 41:   PetscOptionsHasName(NULL,"-verbose",&verbose);
 42:   PetscOptionsHasName(NULL,"-extrarow",&extrarow);

 44:   /* Create DS object */
 45:   DSCreate(PETSC_COMM_WORLD,&ds);
 46:   DSSetType(ds,DSHEP);
 47:   DSSetFromOptions(ds);
 48:   ld = n+2;  /* test leading dimension larger than n */
 49:   DSAllocate(ds,ld);
 50:   DSSetDimensions(ds,n,0,0,0);
 51:   DSSetExtraRow(ds,extrarow);

 53:   /* Set up viewer */
 54:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 55:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 56:   DSView(ds,viewer);
 57:   PetscViewerPopFormat(viewer);
 58:   if (verbose) {
 59:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 60:   }

 62:   /* Fill with a symmetric Toeplitz matrix */
 63:   DSGetArray(ds,DS_MAT_A,&A);
 64:   for (i=0;i<n;i++) A[i+i*ld]=2.0;
 65:   for (j=1;j<3;j++) {
 66:     for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
 67:   }
 68:   if (extrarow) { A[n+(n-2)*ld]=1.0; A[n+(n-1)*ld]=1.0; }
 69:   DSRestoreArray(ds,DS_MAT_A,&A);
 70:   DSSetState(ds,DS_STATE_RAW);
 71:   if (verbose) {
 72:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 73:     DSView(ds,viewer);
 74:   }

 76:   /* Solve */
 77:   PetscMalloc(n*sizeof(PetscScalar),&eig);
 78:   DSSetEigenvalueComparison(ds,SlepcCompareLargestMagnitude,NULL);
 79:   DSSolve(ds,eig,NULL);
 80:   DSSort(ds,eig,NULL,NULL,NULL,NULL);
 81:   if (extrarow) { DSUpdateExtraRow(ds); }
 82:   if (verbose) {
 83:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 84:     DSView(ds,viewer);
 85:   }

 87:   /* Print eigenvalues */
 88:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n",n);
 89:   for (i=0;i<n;i++) {
 90:     PetscViewerASCIIPrintf(viewer,"  %.5F\n",PetscRealPart(eig[i]));
 91:   }

 93:   PetscFree(eig);
 94:   DSDestroy(&ds);
 95:   SlepcFinalize();
 96:   return 0;
 97: }