Date: 2026-03-31T13:23:15+00:00

Actual source code: test3.c

      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 with compact storage.\n\n";

     13: #include <slepcds.h>

     15: int main(int argc,char **argv)
     16: {
     17:   DS             ds;
     18:   SlepcSC        sc;
     19:   PetscReal      *T;
     20:   PetscScalar    *Q,*eig,d;
     21:   PetscInt       i,n=10,l=2,k=5,ld;
     22:   PetscViewer    viewer;
     23:   PetscBool      verbose,extrarow;

     25:   PetscFunctionBeginUser;
     26:   PetscCall(SlepcInitialize(&argc,&argv,NULL,help));
     27:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL));
     28:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type HEP with compact storage - dimension %" PetscInt_FMT ".\n",n));
     29:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL));
     30:   PetscCall(PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL));
     31:   PetscCheck(l<=n && k<=n && l<=k,PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"Wrong value of dimensions");
     32:   PetscCall(PetscOptionsHasName(NULL,NULL,"-verbose",&verbose));
     33:   PetscCall(PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow));

     35:   /* Create DS object */
     36:   PetscCall(DSCreate(PETSC_COMM_WORLD,&ds));
     37:   PetscCall(DSSetType(ds,DSHEP));
     38:   PetscCall(DSSetFromOptions(ds));
     39:   ld = n+2;  /* test leading dimension larger than n */
     40:   PetscCall(DSAllocate(ds,ld));
     41:   PetscCall(DSSetDimensions(ds,n,l,k));
     42:   PetscCall(DSSetCompact(ds,PETSC_TRUE));
     43:   PetscCall(DSSetExtraRow(ds,extrarow));

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

     52:   /* Fill arrow-tridiagonal matrix */
     53:   PetscCall(DSGetArrayReal(ds,DS_MAT_T,&T));
     54:   for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
     55:   for (i=l;i<n-1;i++) T[i+ld] = 1.0;
     56:   if (extrarow) T[n-1+ld] = 1.0;
     57:   PetscCall(DSRestoreArrayReal(ds,DS_MAT_T,&T));
     58:   if (l==0 && k==0) PetscCall(DSSetState(ds,DS_STATE_INTERMEDIATE));
     59:   else PetscCall(DSSetState(ds,DS_STATE_RAW));
     60:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n"));
     61:   PetscCall(DSView(ds,viewer));

     63:   /* Solve */
     64:   PetscCall(PetscMalloc1(n,&eig));
     65:   PetscCall(DSGetSlepcSC(ds,&sc));
     66:   sc->comparison    = SlepcCompareLargestMagnitude;
     67:   sc->comparisonctx = NULL;
     68:   sc->map           = NULL;
     69:   sc->mapobj        = NULL;
     70:   PetscCall(DSSolve(ds,eig,NULL));
     71:   PetscCall(DSSort(ds,eig,NULL,NULL,NULL,NULL));
     72:   if (extrarow) PetscCall(DSUpdateExtraRow(ds));
     73:   if (verbose) {
     74:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n"));
     75:     PetscCall(DSView(ds,viewer));
     76:   }

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

     82:   if (extrarow) {
     83:     /* Check that extra row is correct */
     84:     PetscCall(DSGetArrayReal(ds,DS_MAT_T,&T));
     85:     PetscCall(DSGetArray(ds,DS_MAT_Q,&Q));
     86:     d = 0.0;
     87:     for (i=l;i<n;i++) d += T[i+ld]-Q[n-1+i*ld];
     88:     if (PetscAbsScalar(d)>10*PETSC_MACHINE_EPSILON) PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Warning: there is a mismatch in the extra row of %g\n",(double)PetscAbsScalar(d)));
     89:     PetscCall(DSRestoreArrayReal(ds,DS_MAT_T,&T));
     90:     PetscCall(DSRestoreArray(ds,DS_MAT_Q,&Q));
     91:   }
     92:   PetscCall(PetscFree(eig));
     93:   PetscCall(DSDestroy(&ds));
     94:   PetscCall(SlepcFinalize());
     95:   return 0;
     96: }

     98: /*TEST

    100:    testset:
    101:       args: -n 9 -ds_method {{0 1 2}}
    102:       filter: grep -v "solving the problem" | sed -e "s/extrarow//"
    103:       requires: !single
    104:       test:
    105:          suffix: 1
    106:       test:
    107:          suffix: 2
    108:          args: -extrarow

    110: TEST*/