Actual source code: test8.c

  1: /*
  2:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
  3:    SLEPc - Scalable Library for Eigenvalue Problem Computations
  4:    Copyright (c) 2002-2012, Universitat Politecnica de Valencia, Spain

  6:    This file is part of SLEPc.
  7:       
  8:    SLEPc is free software: you can redistribute it and/or modify it under  the
  9:    terms of version 3 of the GNU Lesser General Public License as published by
 10:    the Free Software Foundation.

 12:    SLEPc  is  distributed in the hope that it will be useful, but WITHOUT  ANY 
 13:    WARRANTY;  without even the implied warranty of MERCHANTABILITY or  FITNESS 
 14:    FOR  A  PARTICULAR PURPOSE. See the GNU Lesser General Public  License  for 
 15:    more details.

 17:    You  should have received a copy of the GNU Lesser General  Public  License
 18:    along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
 19:    - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
 20: */

 22: static char help[] = "Test DSSVD with compact storage.\n\n";

 24:  #include slepcds.h

 28: int main( int argc, char **argv )
 29: {
 31:   DS             ds;
 32:   PetscReal      *T,sigma;
 33:   PetscScalar    *w;
 34:   PetscInt       i,n=10,m,l=2,k=5,ld;
 35:   PetscViewer    viewer;
 36:   PetscBool      verbose;

 38:   SlepcInitialize(&argc,&argv,(char*)0,help);
 39:   PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);
 40:   m = n;
 41:   PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD with compact storage - dimension %Dx%D.\n",n,m);
 42:   PetscOptionsGetInt(PETSC_NULL,"-l",&l,PETSC_NULL);
 43:   PetscOptionsGetInt(PETSC_NULL,"-k",&k,PETSC_NULL);
 44:   if (l>n || k>n || l>k) SETERRQ(PETSC_COMM_WORLD,1,"Wrong value of dimensions");
 45:   PetscOptionsHasName(PETSC_NULL,"-verbose",&verbose);

 47:   /* Create DS object */
 48:   DSCreate(PETSC_COMM_WORLD,&ds);
 49:   DSSetType(ds,DSSVD);
 50:   DSSetFromOptions(ds);
 51:   ld = n+2;  /* test leading dimension larger than n */
 52:   DSAllocate(ds,ld);
 53:   DSSetDimensions(ds,n,m,l,k);
 54:   DSSetCompact(ds,PETSC_TRUE);

 56:   /* Set up viewer */
 57:   PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
 58:   PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
 59:   DSView(ds,viewer);
 60:   PetscViewerPopFormat(viewer);
 61:   if (verbose) {
 62:     PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
 63:   }

 65:   /* Fill upper arrow-tridiagonal matrix */
 66:   DSGetArrayReal(ds,DS_MAT_T,&T);
 67:   for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
 68:   for (i=l;i<n-1;i++) T[i+ld] = 1.0;
 69:   DSRestoreArrayReal(ds,DS_MAT_T,&T);
 70:   if (l==0 && k==0) {
 71:     DSSetState(ds,DS_STATE_INTERMEDIATE);
 72:   } else {
 73:     DSSetState(ds,DS_STATE_RAW);
 74:   }
 75:   if (verbose) {
 76:     PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
 77:     DSView(ds,viewer);
 78:   }

 80:   /* Solve */
 81:   PetscMalloc(n*sizeof(PetscScalar),&w);
 82:   DSSetEigenvalueComparison(ds,SlepcCompareLargestReal,PETSC_NULL);
 83:   DSSolve(ds,w,PETSC_NULL);
 84:   DSSort(ds,w,PETSC_NULL,PETSC_NULL,PETSC_NULL,PETSC_NULL);
 85:   if (verbose) {
 86:     PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
 87:     DSView(ds,viewer);
 88:   }
 89: 
 90:   /* Print singular values */
 91:   PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n",n);
 92:   for (i=0;i<n;i++) {
 93:     sigma = PetscRealPart(w[i]);
 94:     PetscViewerASCIIPrintf(viewer,"  %.5F\n",sigma);
 95:   }
 96:   PetscFree(w);
 97:   DSDestroy(&ds);
 98:   SlepcFinalize();
 99:   return 0;
100: }