Actual source code: test7.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.\n\n";
24: #include slepcds.h
28: int main( int argc, char **argv )
29: {
31: DS ds;
32: PetscReal sigma;
33: PetscScalar *A,*w;
34: PetscInt i,j,k,n=15,m=10,ld;
35: PetscViewer viewer;
36: PetscBool verbose;
38: SlepcInitialize(&argc,&argv,(char*)0,help);
39: PetscOptionsGetInt(PETSC_NULL,"-n",&n,PETSC_NULL);
40: PetscOptionsGetInt(PETSC_NULL,"-m",&m,PETSC_NULL);
41: k = PetscMin(n,m);
42: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD - dimension %Dx%D.\n",n,m);
43: PetscOptionsHasName(PETSC_NULL,"-verbose",&verbose);
45: /* Create DS object */
46: DSCreate(PETSC_COMM_WORLD,&ds);
47: DSSetType(ds,DSSVD);
48: DSSetFromOptions(ds);
49: ld = n+2; /* test leading dimension larger than n */
50: DSAllocate(ds,ld);
51: DSSetDimensions(ds,n,m,0,0);
53: /* Set up viewer */
54: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
55: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
56: DSView(ds,viewer);
57: PetscViewerPopFormat(viewer);
58: if (verbose) {
59: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
60: }
62: /* Fill with a rectangular Toeplitz matrix */
63: DSGetArray(ds,DS_MAT_A,&A);
64: for (i=0;i<k;i++) A[i+i*ld]=1.0;
65: for (j=1;j<3;j++) {
66: for (i=0;i<n-j;i++) { if ((i+j)<m) A[i+(i+j)*ld]=(PetscScalar)(j+1); }
67: }
68: for (j=1;j<n/2;j++) {
69: for (i=0;i<n-j;i++) { if ((i+j)<n && i<m) A[(i+j)+i*ld]=-1.0; }
70: }
71: DSRestoreArray(ds,DS_MAT_A,&A);
72: DSSetState(ds,DS_STATE_RAW);
73: if (verbose) {
74: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
75: DSView(ds,viewer);
76: }
78: /* Solve */
79: PetscMalloc(k*sizeof(PetscScalar),&w);
80: DSSetEigenvalueComparison(ds,SlepcCompareLargestReal,PETSC_NULL);
81: DSSolve(ds,w,PETSC_NULL);
82: DSSort(ds,w,PETSC_NULL,PETSC_NULL,PETSC_NULL,PETSC_NULL);
83: if (verbose) {
84: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
85: DSView(ds,viewer);
86: }
87:
88: /* Print singular values */
89: PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n",n);
90: for (i=0;i<k;i++) {
91: sigma = PetscRealPart(w[i]);
92: PetscViewerASCIIPrintf(viewer," %.5F\n",sigma);
93: }
94: PetscFree(w);
95: DSDestroy(&ds);
96: SlepcFinalize();
97: return 0;
98: }