Date: 2023-09-05T10:19:02+00:00

Actual source code: test4.c
slepc-3.19.2 2023-09-05
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-, 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 DSGNHEP.\n\n";

     13: #include <slepcds.h>

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

     25:   PetscFunctionBeginUser;
     26:   PetscCall(SlepcInitialize(&argc,&argv,(char*)0,help));
     27:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     28:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GNHEP - dimension %" PetscInt_FMT ".\n",n));
     29:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));

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

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

     46:   /* Fill A with Grcar matrix */
     47:   PetscCall(DSGetArray(ds,DS_MAT_A,&A));
     48:   PetscCall(PetscArrayzero(A,ld*n));
     49:   for (i=1;i<n;i++) A[i+(i-1)*ld]=-1.0;
     50:   for (j=0;j<4;j++) {
     51:     for (i=0;i<n-j;i++) A[i+(i+j)*ld]=1.0;
     52:   }
     53:   PetscCall(DSRestoreArray(ds,DS_MAT_A,&A));
     54:   /* Fill B with an upper triangular matrix */
     55:   PetscCall(DSGetArray(ds,DS_MAT_B,&B));
     56:   PetscCall(PetscArrayzero(B,ld*n));
     57:   B[0+0*ld]=-1.0;
     58:   B[0+1*ld]=2.0;
     59:   for (i=1;i<n;i++) B[i+i*ld]=1.0;
     60:   PetscCall(DSRestoreArray(ds,DS_MAT_B,&B));

     62:   if (verbose) {
     63:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n"));
     64:     PetscCall(DSView(ds,viewer));
     65:   }

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

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

     95:   /* Eigenvectors */
     96:   j = 1;
     97:   PetscCall(DSVectors(ds,DS_MAT_X,&j,&rnorm));  /* second eigenvector */
     98:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm));
     99:   PetscCall(DSVectors(ds,DS_MAT_X,NULL,NULL));  /* all eigenvectors */
    100:   j = 0;
    101:   rnorm = 0.0;
    102:   PetscCall(DSGetArray(ds,DS_MAT_X,&X));
    103:   for (i=0;i<n;i++) {
    104: #if defined(PETSC_USE_COMPLEX)
    105:     aux = PetscAbsScalar(X[i+j*ld]);
    106: #else
    107:     if (PetscAbs(wi[j])==0.0) aux = PetscAbsScalar(X[i+j*ld]);
    108:     else aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
    109: #endif
    110:     rnorm += aux*aux;
    111:   }
    112:   PetscCall(DSRestoreArray(ds,DS_MAT_X,&X));
    113:   rnorm = PetscSqrtReal(rnorm);
    114:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm));
    115:   if (verbose) {
    116:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n"));
    117:     PetscCall(DSView(ds,viewer));
    118:   }

    120:   PetscCall(PetscFree2(wr,wi));
    121:   PetscCall(DSDestroy(&ds));
    122:   PetscCall(SlepcFinalize());
    123:   return 0;
    124: }

    126: /*TEST

    128:    test:
    129:       suffix: 1
    130:       filter: sed -e "s/[+-]\([0-9]\.[0-9]*i\)/+-\\1/" | sed -e "s/+-0\.0*i//"

    132: TEST*/