Date: 2023-11-27T17:19:38+00:00

Actual source code: test15.c
slepc-3.20.1 2023-11-27
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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 DSPEP.\n\n";

     13: #include <slepcds.h>

     15: int main(int argc,char **argv)
     16: {
     17:   DS             ds;
     18:   SlepcSC        sc;
     19:   Mat            X;
     20:   Vec            x0;
     21:   PetscScalar    *K,*C,*M,*wr,*wi,z=1.0;
     22:   PetscReal      re,im,nrm,*pbc;
     23:   PetscInt       i,j,n=10,d=2,ld;
     24:   PetscViewer    viewer;
     25:   PetscBool      verbose;

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

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

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

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

     51:   /* Fill matrices */
     52:   PetscCall(DSGetArray(ds,DS_MAT_E0,&K));
     53:   for (i=0;i<n-1;i++) K[i+i*ld] = 2.0*n;
     54:   K[n-1+(n-1)*ld] = 1.0*n;
     55:   for (i=1;i<n;i++) {
     56:     K[i+(i-1)*ld] = -1.0*n;
     57:     K[(i-1)+i*ld] = -1.0*n;
     58:   }
     59:   PetscCall(DSRestoreArray(ds,DS_MAT_E0,&K));
     60:   PetscCall(DSGetArray(ds,DS_MAT_E1,&C));
     61:   C[n-1+(n-1)*ld] = 2.0*PETSC_PI/z;
     62:   PetscCall(DSRestoreArray(ds,DS_MAT_E1,&C));
     63:   PetscCall(DSGetArray(ds,DS_MAT_E2,&M));
     64:   for (i=0;i<n-1;i++) M[i+i*ld] = -4.0*PETSC_PI*PETSC_PI/n;
     65:   M[i+i*ld] = -2.0*PETSC_PI*PETSC_PI/n;
     66:   PetscCall(DSRestoreArray(ds,DS_MAT_E2,&M));

     68:   if (verbose) {
     69:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n"));
     70:     PetscCall(DSView(ds,viewer));
     71:   }

     73:   /* Solve */
     74:   PetscCall(PetscMalloc2(d*n,&wr,d*n,&wi));
     75:   PetscCall(DSGetSlepcSC(ds,&sc));
     76:   sc->comparison    = SlepcCompareLargestReal;
     77:   sc->comparisonctx = NULL;
     78:   sc->map           = NULL;
     79:   sc->mapobj        = NULL;
     80:   PetscCall(DSSolve(ds,wr,wi));
     81:   PetscCall(DSSort(ds,wr,wi,NULL,NULL,NULL));
     82:   if (verbose) {
     83:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n"));
     84:     PetscCall(DSView(ds,viewer));
     85:   }

     87:   /* Print polynomial coefficients */
     88:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Polynomial coefficients (alpha,beta,gamma) =\n"));
     89:   PetscCall(DSPEPGetCoefficients(ds,&pbc));
     90:   for (j=0;j<3;j++) {
     91:     for (i=0;i<d+1;i++) PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f",(double)pbc[j+3*i]));
     92:     PetscCall(PetscViewerASCIIPrintf(viewer,"\n"));
     93:   }
     94:   PetscCall(PetscFree(pbc));

     96:   /* Print eigenvalues */
     97:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n"));
     98:   for (i=0;i<d*n;i++) {
     99: #if defined(PETSC_USE_COMPLEX)
    100:     re = PetscRealPart(wr[i]);
    101:     im = PetscImaginaryPart(wr[i]);
    102: #else
    103:     re = wr[i];
    104:     im = wi[i];
    105: #endif
    106:     if (PetscAbs(im)<1e-10) PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)re));
    107:     else PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f%+.5fi\n",(double)re,(double)im));
    108:   }

    110:   /* Eigenvectors */
    111:   PetscCall(DSVectors(ds,DS_MAT_X,NULL,NULL));  /* all eigenvectors */
    112:   PetscCall(DSGetMat(ds,DS_MAT_X,&X));
    113:   PetscCall(MatCreateVecs(X,NULL,&x0));
    114:   PetscCall(MatGetColumnVector(X,x0,0));
    115:   PetscCall(VecNorm(x0,NORM_2,&nrm));
    116:   PetscCall(DSRestoreMat(ds,DS_MAT_X,&X));
    117:   PetscCall(VecDestroy(&x0));
    118:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)nrm));
    119:   if (verbose) {
    120:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n"));
    121:     PetscCall(DSView(ds,viewer));
    122:   }

    124:   PetscCall(PetscFree2(wr,wi));
    125:   PetscCall(DSDestroy(&ds));
    126:   PetscCall(SlepcFinalize());
    127:   return 0;
    128: }

    130: /*TEST

    132:    test:
    133:       suffix: 1
    134:       requires: !single

    136: TEST*/