Date: 2022-03-31T15:28:53+00:00

Actual source code: test8.c
slepc-3.17.0 2022-03-31
Report Typos and Errors

      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 DSSVD 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,sigma;
     20:   PetscScalar    *U,*w,d;
     21:   PetscInt       i,n=10,m,l=2,k=5,ld;
     22:   PetscViewer    viewer;
     23:   PetscBool      verbose,extrarow;

     25:   SlepcInitialize(&argc,&argv,(char*)0,help);
     26:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     27:   m = n;
     28:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD with compact storage - dimension %" PetscInt_FMT "x%" PetscInt_FMT ".\n",n,m);
     29:   PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL);
     30:   PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
     32:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
     33:   PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow);

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

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

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

     64:   /* Solve */
     65:   PetscMalloc1(n,&w);
     66:   DSGetSlepcSC(ds,&sc);
     67:   sc->comparison    = SlepcCompareLargestReal;
     68:   sc->comparisonctx = NULL;
     69:   sc->map           = NULL;
     70:   sc->mapobj        = NULL;
     71:   DSSolve(ds,w,NULL);
     72:   DSSort(ds,w,NULL,NULL,NULL,NULL);
     73:   if (extrarow) DSUpdateExtraRow(ds);
     74:   if (verbose) {
     75:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
     76:     DSView(ds,viewer);
     77:   }

     79:   /* Print singular values */
     80:   PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n");
     81:   for (i=0;i<n;i++) {
     82:     sigma = PetscRealPart(w[i]);
     83:     PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)sigma);
     84:   }

     86:   if (extrarow) {
     87:     /* Check that extra row is correct */
     88:     DSGetArrayReal(ds,DS_MAT_T,&T);
     89:     DSGetArray(ds,DS_MAT_U,&U);
     90:     d = 0.0;
     91:     for (i=l;i<n;i++) d += T[i+ld]-U[n-1+i*ld];
     92:     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));
     93:     DSRestoreArrayReal(ds,DS_MAT_T,&T);
     94:     DSRestoreArray(ds,DS_MAT_U,&U);
     95:   }
     96:   PetscFree(w);
     97:   DSDestroy(&ds);
     98:   SlepcFinalize();
     99:   return 0;
    100: }

    102: /*TEST

    104:    test:
    105:       suffix: 1
    106:       requires: !single

    108:    test:
    109:       args: -l 0 -k 0
    110:       suffix: 2
    111:       requires: !single

    113:    test:
    114:       args: -extrarow
    115:       suffix: 3
    116:       requires: !single

    118: TEST*/