Date: 2021-02-01T14:41:45+00:00

Actual source code: test5.c
slepc-3.14.2 2021-02-01
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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[] = "Test DSGHIEP.\n\n";

     13: #include <slepcds.h>

     15: int main(int argc,char **argv)
     16: {
     18:   DS             ds;
     19:   SlepcSC        sc;
     20:   PetscReal      re,im;
     21:   PetscScalar    *A,*B,*eigr,*eigi;
     22:   PetscInt       i,j,n=10,ld;
     23:   PetscViewer    viewer;
     24:   PetscBool      verbose;

     26:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
     27:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     28:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GHIEP - dimension %D.\n",n);
     29:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

     31:   /* Create DS object */
     32:   DSCreate(PETSC_COMM_WORLD,&ds);
     33:   DSSetType(ds,DSGHIEP);
     34:   DSSetFromOptions(ds);
     35:   ld = n+2;  /* test leading dimension larger than n */
     36:   DSAllocate(ds,ld);
     37:   DSSetDimensions(ds,n,0,0,0);

     39:   /* Set up viewer */
     40:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
     41:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
     42:   DSView(ds,viewer);
     43:   PetscViewerPopFormat(viewer);
     44:   if (verbose) {
     45:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
     46:   }

     48:   /* Fill with a symmetric Toeplitz matrix */
     49:   DSGetArray(ds,DS_MAT_A,&A);
     50:   DSGetArray(ds,DS_MAT_B,&B);
     51:   for (i=0;i<n;i++) A[i+i*ld]=2.0;
     52:   for (j=1;j<3;j++) {
     53:     for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
     54:   }
     55:   for (j=1;j<3;j++) { A[0+j*ld]=-1.0*(j+2); A[j+0*ld]=-1.0*(j+2); }
     56:   /* Signature matrix */
     57:   for (i=0;i<n;i++) B[i+i*ld]=1.0;
     58:   B[0] = -1.0;
     59:   B[n-1+(n-1)*ld] = -1.0;
     60:   DSRestoreArray(ds,DS_MAT_A,&A);
     61:   DSRestoreArray(ds,DS_MAT_B,&B);
     62:   DSSetState(ds,DS_STATE_RAW);
     63:   if (verbose) {
     64:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
     65:     DSView(ds,viewer);
     66:   }

     68:   /* Solve */
     69:   PetscCalloc2(n,&eigr,n,&eigi);
     70:   DSGetSlepcSC(ds,&sc);
     71:   sc->comparison    = SlepcCompareLargestMagnitude;
     72:   sc->comparisonctx = NULL;
     73:   sc->map           = NULL;
     74:   sc->mapobj        = NULL;
     75:   DSSolve(ds,eigr,eigi);
     76:   DSSort(ds,eigr,eigi,NULL,NULL,NULL);
     77:   if (verbose) {
     78:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
     79:     DSView(ds,viewer);
     80:   }

     82:   /* Print eigenvalues */
     83:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
     84:   for (i=0;i<n;i++) {
     85: #if defined(PETSC_USE_COMPLEX)
     86:     re = PetscRealPart(eigr[i]);
     87:     im = PetscImaginaryPart(eigr[i]);
     88: #else
     89:     re = eigr[i];
     90:     im = eigi[i];
     91: #endif
     92:     if (PetscAbs(im)<1e-10) {
     93:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
     94:     } else {
     95:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
     96:     }
     97:   }
     98:   PetscFree2(eigr,eigi);
     99:   DSDestroy(&ds);
    100:   SlepcFinalize();
    101:   return ierr;
    102: }

    104: /*TEST

    106:    test:
    107:       suffix: 1
    108:       requires: !single
    109:       args: -ds_method {{0 1 2}}
    110:       filter: grep -v "solving the problem"

    112: TEST*/