Date: 2022-03-31T15:28:52+00:00

Actual source code: test2.c
slepc-3.17.0 2022-03-31
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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 DSHEP.\n\n";

     13: #include <slepcds.h>

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

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

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

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

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

     61:   /* Solve */
     62:   PetscMalloc1(n,&eig);
     63:   DSGetSlepcSC(ds,&sc);
     64:   sc->comparison    = SlepcCompareLargestMagnitude;
     65:   sc->comparisonctx = NULL;
     66:   sc->map           = NULL;
     67:   sc->mapobj        = NULL;
     68:   DSSolve(ds,eig,NULL);
     69:   DSSort(ds,eig,NULL,NULL,NULL,NULL);
     70:   if (extrarow) DSUpdateExtraRow(ds);
     71:   if (verbose) {
     72:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
     73:     DSView(ds,viewer);
     74:   }

     76:   /* Print eigenvalues */
     77:   PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
     78:   for (i=0;i<n;i++) PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)PetscRealPart(eig[i]));

     80:   if (extrarow) {
     81:     /* Check that extra row is correct */
     82:     DSGetArray(ds,DS_MAT_A,&A);
     83:     DSGetArray(ds,DS_MAT_Q,&Q);
     84:     d = 0.0;
     85:     for (i=0;i<n;i++) d += A[n+i*ld]-Q[n-2+i*ld]-Q[n-1+i*ld];
     86:     if (PetscAbsScalar(d)>10*PETSC_MACHINE_EPSILON) PetscPrintf(PETSC_COMM_WORLD,"Warning: there is a mismatch in the extra row of %g\n",(double)PetscAbsScalar(d));
     87:     DSRestoreArray(ds,DS_MAT_A,&A);
     88:     DSRestoreArray(ds,DS_MAT_Q,&Q);
     89:   }

     91:   /* Eigenvectors */
     92:   j = 2;
     93:   DSVectors(ds,DS_MAT_X,&j,&rnorm);  /* third eigenvector */
     94:   PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 3rd vector = %.3f\n",(double)rnorm);
     95:   DSVectors(ds,DS_MAT_X,NULL,NULL);  /* all eigenvectors */
     96:   j = 0;
     97:   rnorm = 0.0;
     98:   DSGetArray(ds,DS_MAT_X,&X);
     99:   for (i=0;i<n;i++) {
    100:     aux = PetscAbsScalar(X[i+j*ld]);
    101:     rnorm += aux*aux;
    102:   }
    103:   DSRestoreArray(ds,DS_MAT_X,&X);
    104:   rnorm = PetscSqrtReal(rnorm);
    105:   PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
    106:   if (verbose) {
    107:     PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
    108:     DSView(ds,viewer);
    109:   }

    111:   PetscFree(eig);
    112:   DSDestroy(&ds);
    113:   SlepcFinalize();
    114:   return 0;
    115: }

    117: /*TEST

    119:    testset:
    120:       args: -n 12 -ds_method {{0 1 2}}
    121:       filter: grep -v "solving the problem" | sed -e "s/extrarow//"
    122:       output_file: output/test2_1.out
    123:       requires: !single
    124:       test:
    125:          suffix: 1
    126:       test:
    127:          suffix: 2
    128:          args: -extrarow

    130: TEST*/