Date: 2021-02-01T14:41:45+00:00

Actual source code: test8.c
slepc-3.14.2 2021-02-01
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      1: /*
      2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
      3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
      4:    Copyright (c) 2002-2020, 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: {
     18:   DS             ds;
     19:   SlepcSC        sc;
     20:   PetscReal      *T,sigma;
     21:   PetscScalar    *w;
     22:   PetscInt       i,n=10,m,l=2,k=5,ld;
     23:   PetscViewer    viewer;
     24:   PetscBool      verbose;

     26:   SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
     27:   PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
     28:   m = n;
     29:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD with compact storage - dimension %Dx%D.\n",n,m);
     30:   PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL);
     31:   PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
     32:   if (l>n || k>n || l>k) SETERRQ(PETSC_COMM_WORLD,1,"Wrong value of dimensions");
     33:   PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);

     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,m,l,k);
     42:   DSSetCompact(ds,PETSC_TRUE);

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

     51:   /* Fill upper arrow-tridiagonal matrix */
     52:   DSGetArrayReal(ds,DS_MAT_T,&T);
     53:   for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
     54:   for (i=l;i<n-1;i++) T[i+ld] = 1.0;
     55:   DSRestoreArrayReal(ds,DS_MAT_T,&T);
     56:   if (l==0 && k==0) {
     57:     DSSetState(ds,DS_STATE_INTERMEDIATE);
     58:   } else {
     59:     DSSetState(ds,DS_STATE_RAW);
     60:   }
     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 (verbose) {
     74:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
     75:     DSView(ds,viewer);
     76:   }

     78:   /* Print singular values */
     79:   PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n");
     80:   for (i=0;i<n;i++) {
     81:     sigma = PetscRealPart(w[i]);
     82:     PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)sigma);
     83:   }
     84:   PetscFree(w);
     85:   DSDestroy(&ds);
     86:   SlepcFinalize();
     87:   return ierr;
     88: }

     90: /*TEST

     92:    test:
     93:       suffix: 1
     94:       requires: !single

     96: TEST*/