Date: 2016-03-29T14:57:01+00:00

Actual source code: test5.c
slepc-3.6.3 2016-03-29
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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 DSGHIEP.\n\n";

     24: #include <slepcds.h>

     28: int main(int argc,char **argv)
     29: {
     31:   DS             ds;
     32:   SlepcSC        sc;
     33:   PetscReal      re,im;
     34:   PetscScalar    *A,*B,*eigr,*eigi;
     35:   PetscInt       i,j,n=10,ld;
     36:   PetscViewer    viewer;
     37:   PetscBool      verbose;

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

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

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

     61:   /* Fill with a symmetric Toeplitz matrix */
     62:   DSGetArray(ds,DS_MAT_A,&A);
     63:   DSGetArray(ds,DS_MAT_B,&B);
     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:   for (j=1;j<3;j++) { A[0+j*ld]=-1.0*(j+2); A[j+0*ld]=-1.0*(j+2); }
     69:   /* Signature matrix */
     70:   for (i=0;i<n;i++) B[i+i*ld]=1.0;
     71:   B[0] = -1.0;
     72:   B[n-1+(n-1)*ld] = -1.0;
     73:   DSRestoreArray(ds,DS_MAT_A,&A);
     74:   DSRestoreArray(ds,DS_MAT_B,&B);
     75:   DSSetState(ds,DS_STATE_RAW);
     76:   if (verbose) {
     77:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
     78:     DSView(ds,viewer);
     79:   }

     81:   /* Solve */
     82:   PetscCalloc2(n,&eigr,n,&eigi);
     83:   DSGetSlepcSC(ds,&sc);
     84:   sc->comparison    = SlepcCompareLargestMagnitude;
     85:   sc->comparisonctx = NULL;
     86:   sc->map           = NULL;
     87:   sc->mapobj        = NULL;
     88:   DSSolve(ds,eigr,eigi);
     89:   DSSort(ds,eigr,eigi,NULL,NULL,NULL);
     90:   if (verbose) {
     91:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
     92:     DSView(ds,viewer);
     93:   }

     95:   /* Print eigenvalues */
     96:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
     97:   for (i=0;i<n;i++) {
     98: #if defined(PETSC_USE_COMPLEX)
     99:     re = PetscRealPart(eigr[i]);
    100:     im = PetscImaginaryPart(eigr[i]);
    101: #else
    102:     re = eigr[i];
    103:     im = eigi[i];
    104: #endif
    105:     if (PetscAbs(im)<1e-10) {
    106:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
    107:     } else {
    108:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
    109:     }
    110:   }
    111:   PetscFree2(eigr,eigi);
    112:   DSDestroy(&ds);
    113:   SlepcFinalize();
    114:   return 0;
    115: }