Actual source code: test8.c
slepc-3.17.0 2022-03-31
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: SlepcInitialize(&argc,&argv,(char*)0,help);
26: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
27: m = n;
28: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD with compact storage - dimension %" PetscInt_FMT "x%" PetscInt_FMT ".\n",n,m);
29: PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL);
30: PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
32: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
33: PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow);
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,l,k);
42: DSSVDSetDimensions(ds,m);
43: DSSetCompact(ds,PETSC_TRUE);
44: DSSetExtraRow(ds,extrarow);
46: /* Set up viewer */
47: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
48: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
49: DSView(ds,viewer);
50: PetscViewerPopFormat(viewer);
51: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
53: /* Fill upper arrow-bidiagonal matrix */
54: DSGetArrayReal(ds,DS_MAT_T,&T);
55: for (i=0;i<n;i++) T[i] = (PetscReal)(i+1);
56: for (i=l;i<n-1;i++) T[i+ld] = 1.0;
57: if (extrarow) T[n-1+ld] = 1.0;
58: DSRestoreArrayReal(ds,DS_MAT_T,&T);
59: if (l==0 && k==0) DSSetState(ds,DS_STATE_INTERMEDIATE);
60: else DSSetState(ds,DS_STATE_RAW);
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 (extrarow) DSUpdateExtraRow(ds);
74: if (verbose) {
75: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
76: DSView(ds,viewer);
77: }
79: /* Print singular values */
80: PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n");
81: for (i=0;i<n;i++) {
82: sigma = PetscRealPart(w[i]);
83: PetscViewerASCIIPrintf(viewer," %.5f\n",(double)sigma);
84: }
86: if (extrarow) {
87: /* Check that extra row is correct */
88: DSGetArrayReal(ds,DS_MAT_T,&T);
89: DSGetArray(ds,DS_MAT_U,&U);
90: d = 0.0;
91: for (i=l;i<n;i++) d += T[i+ld]-U[n-1+i*ld];
92: if (PetscAbsScalar(d)>10*PETSC_MACHINE_EPSILON) PetscPrintf(PETSC_COMM_WORLD,"Warning: there is a mismatch in the extra row of %g\n",(double)PetscAbsScalar(d));
93: DSRestoreArrayReal(ds,DS_MAT_T,&T);
94: DSRestoreArray(ds,DS_MAT_U,&U);
95: }
96: PetscFree(w);
97: DSDestroy(&ds);
98: SlepcFinalize();
99: return 0;
100: }
102: /*TEST
104: test:
105: suffix: 1
106: requires: !single
108: test:
109: args: -l 0 -k 0
110: suffix: 2
111: requires: !single
113: test:
114: args: -extrarow
115: suffix: 3
116: requires: !single
118: TEST*/