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

Actual source code: test17.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 DSPEP with complex eigenvalues.\n\n";

     13: #include <slepcds.h>

     15: int main(int argc,char **argv)
     16: {
     18:   DS             ds;
     19:   SlepcSC        sc;
     20:   Mat            X;
     21:   Vec            x0;
     22:   PetscScalar    *K,*M,*wr,*wi;
     23:   PetscReal      re,im,nrm;
     24:   PetscInt       i,n=10,d=2,ld;
     25:   PetscViewer    viewer;
     26:   PetscBool      verbose;

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

     33:   /* Create DS object */
     34:   DSCreate(PETSC_COMM_WORLD,&ds);
     35:   DSSetType(ds,DSPEP);
     36:   DSSetFromOptions(ds);
     37:   DSPEPSetDegree(ds,d);

     39:   /* Set dimensions */
     40:   ld = n+2;  /* test leading dimension larger than n */
     41:   DSAllocate(ds,ld);
     42:   DSSetDimensions(ds,n,0,0,0);

     44:   /* Set up viewer */
     45:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
     46:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
     47:   DSView(ds,viewer);
     48:   PetscViewerPopFormat(viewer);
     49:   if (verbose) {
     50:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
     51:   }

     53:   /* Fill matrices */
     54:   DSGetArray(ds,DS_MAT_E0,&K);
     55:   for (i=0;i<n;i++) K[i+i*ld] = 2.0;
     56:   for (i=1;i<n;i++) {
     57:     K[i+(i-1)*ld] = -1.0;
     58:     K[(i-1)+i*ld] = -1.0;
     59:   }
     60:   DSRestoreArray(ds,DS_MAT_E0,&K);
     61:   DSGetArray(ds,DS_MAT_E2,&M);
     62:   for (i=0;i<n;i++) M[i+i*ld] = 1.0;
     63:   DSRestoreArray(ds,DS_MAT_E2,&M);

     65:   if (verbose) {
     66:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
     67:     DSView(ds,viewer);
     68:   }

     70:   /* Solve */
     71:   PetscMalloc2(d*n,&wr,d*n,&wi);
     72:   DSGetSlepcSC(ds,&sc);
     73:   sc->comparison    = SlepcCompareLargestImaginary;
     74:   sc->comparisonctx = NULL;
     75:   sc->map           = NULL;
     76:   sc->mapobj        = NULL;
     77:   DSSolve(ds,wr,wi);
     78:   DSSort(ds,wr,wi,NULL,NULL,NULL);
     79:   if (verbose) {
     80:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
     81:     DSView(ds,viewer);
     82:   }

     84:   /* Print eigenvalues */
     85:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
     86:   for (i=0;i<d*n;i++) {
     87: #if defined(PETSC_USE_COMPLEX)
     88:     re = PetscRealPart(wr[i]);
     89:     im = PetscImaginaryPart(wr[i]);
     90: #else
     91:     re = wr[i];
     92:     im = wi[i];
     93: #endif
     94:     if (PetscAbs(im)<1e-10) {
     95:       PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re);
     96:     } else {
     97:       PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im);
     98:     }
     99:   }

    101:   /* Eigenvectors */
    102:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
    103:   DSGetMat(ds,DS_MAT_X,&X);
    104:   MatCreateVecs(X,NULL,&x0);
    105:   MatGetColumnVector(X,x0,1);
    106:   VecNorm(x0,NORM_2,&nrm);
    107:   MatDestroy(&X);
    108:   VecDestroy(&x0);
    109:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 2nd column of X = %.3f\n",(double)nrm);
    110:   if (verbose) {
    111:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
    112:     DSView(ds,viewer);
    113:   }

    115:   PetscFree2(wr,wi);
    116:   DSDestroy(&ds);
    117:   SlepcFinalize();
    118:   return ierr;
    119: }

    121: /*TEST

    123:    test:
    124:       suffix: 1
    125:       args: -n 7
    126:       requires: !complex

    128:    test:
    129:       suffix: 1_complex
    130:       args: -n 7
    131:       requires: complex

    133: TEST*/