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

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

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

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

 65:   /* Solve */
 66:   PetscCall(PetscMalloc1(n,&w));
 67:   PetscCall(DSGetSlepcSC(ds,&sc));
 68:   sc->comparison    = SlepcCompareLargestReal;
 69:   sc->comparisonctx = NULL;
 70:   sc->map           = NULL;
 71:   sc->mapobj        = NULL;
 72:   PetscCall(DSSolve(ds,w,NULL));
 73:   PetscCall(DSSort(ds,w,NULL,NULL,NULL,NULL));
 74:   if (extrarow) PetscCall(DSUpdateExtraRow(ds));
 75:   if (verbose) {
 76:     PetscCall(PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n"));
 77:     PetscCall(DSView(ds,viewer));
 78:   }

 80:   /* Print singular values */
 81:   PetscCall(PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n"));
 82:   for (i=0;i<n;i++) {
 83:     sigma = PetscRealPart(w[i]);
 84:     PetscCall(PetscViewerASCIIPrintf(viewer,"  %.5f\n",(double)sigma));
 85:   }

 87:   if (extrarow) {
 88:     /* Check that extra row is correct */
 89:     PetscCall(DSGetArrayReal(ds,DS_MAT_T,&T));
 90:     PetscCall(DSGetArray(ds,DS_MAT_U,&U));
 91:     d = 0.0;
 92:     for (i=l;i<n;i++) d += T[i+ld]-U[n-1+i*ld];
 93:     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)));
 94:     PetscCall(DSRestoreArrayReal(ds,DS_MAT_T,&T));
 95:     PetscCall(DSRestoreArray(ds,DS_MAT_U,&U));
 96:   }
 97:   PetscCall(PetscFree(w));
 98:   PetscCall(DSDestroy(&ds));
 99:   PetscCall(SlepcFinalize());
100:   return 0;
101: }

103: /*TEST

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

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

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

119: TEST*/