Actual source code: test8.c
slepc-3.6.1 2015-09-03
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2015, Universitat Politecnica de Valencia, Spain
6: This file is part of SLEPc.
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: SlepcSC sc;
33: PetscReal *T,sigma;
34: PetscScalar *w;
35: PetscInt i,n=10,m,l=2,k=5,ld;
36: PetscViewer viewer;
37: PetscBool verbose;
39: SlepcInitialize(&argc,&argv,(char*)0,help);
40: PetscOptionsGetInt(NULL,"-n",&n,NULL);
41: m = n;
42: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD with compact storage - dimension %Dx%D.\n",n,m);
43: PetscOptionsGetInt(NULL,"-l",&l,NULL);
44: PetscOptionsGetInt(NULL,"-k",&k,NULL);
45: if (l>n || k>n || l>k) SETERRQ(PETSC_COMM_WORLD,1,"Wrong value of dimensions");
46: PetscOptionsHasName(NULL,"-verbose",&verbose);
48: /* Create DS object */
49: DSCreate(PETSC_COMM_WORLD,&ds);
50: DSSetType(ds,DSSVD);
51: DSSetFromOptions(ds);
52: ld = n+2; /* test leading dimension larger than n */
53: DSAllocate(ds,ld);
54: DSSetDimensions(ds,n,m,l,k);
55: DSSetCompact(ds,PETSC_TRUE);
57: /* Set up viewer */
58: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
59: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
60: DSView(ds,viewer);
61: PetscViewerPopFormat(viewer);
62: if (verbose) {
63: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
64: }
66: /* Fill upper arrow-tridiagonal matrix */
67: DSGetArrayReal(ds,DS_MAT_T,&T);
68: for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
69: for (i=l;i<n-1;i++) T[i+ld] = 1.0;
70: DSRestoreArrayReal(ds,DS_MAT_T,&T);
71: if (l==0 && k==0) {
72: DSSetState(ds,DS_STATE_INTERMEDIATE);
73: } else {
74: DSSetState(ds,DS_STATE_RAW);
75: }
76: if (verbose) {
77: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
78: DSView(ds,viewer);
79: }
81: /* Solve */
82: PetscMalloc1(n,&w);
83: DSGetSlepcSC(ds,&sc);
84: sc->comparison = SlepcCompareLargestReal;
85: sc->comparisonctx = NULL;
86: sc->map = NULL;
87: sc->mapobj = NULL;
88: DSSolve(ds,w,NULL);
89: DSSort(ds,w,NULL,NULL,NULL,NULL);
90: if (verbose) {
91: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
92: DSView(ds,viewer);
93: }
95: /* Print singular values */
96: PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n");
97: for (i=0;i<n;i++) {
98: sigma = PetscRealPart(w[i]);
99: PetscViewerASCIIPrintf(viewer," %.5f\n",(double)sigma);
100: }
101: PetscFree(w);
102: DSDestroy(&ds);
103: SlepcFinalize();
104: return 0;
105: }