Actual source code: test8.c
slepc-3.16.3 2022-04-11
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2021, 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: {
18: DS ds;
19: SlepcSC sc;
20: PetscReal *T,sigma;
21: PetscScalar *U,*w,d;
22: PetscInt i,n=10,m,l=2,k=5,ld;
23: PetscViewer viewer;
24: PetscBool verbose,extrarow;
26: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
27: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
28: m = n;
29: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type SVD with compact storage - dimension %Dx%D.\n",n,m);
30: PetscOptionsGetInt(NULL,NULL,"-l",&l,NULL);
31: PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
32: if (l>n || k>n || l>k) SETERRQ(PETSC_COMM_WORLD,PETSC_ERR_USER_INPUT,"Wrong value of dimensions");
33: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
34: PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow);
36: /* Create DS object */
37: DSCreate(PETSC_COMM_WORLD,&ds);
38: DSSetType(ds,DSSVD);
39: DSSetFromOptions(ds);
40: ld = n+2; /* test leading dimension larger than n */
41: DSAllocate(ds,ld);
42: DSSetDimensions(ds,n,l,k);
43: DSSVDSetDimensions(ds,m);
44: DSSetCompact(ds,PETSC_TRUE);
45: DSSetExtraRow(ds,extrarow);
47: /* Set up viewer */
48: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
49: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
50: DSView(ds,viewer);
51: PetscViewerPopFormat(viewer);
52: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
54: /* Fill upper arrow-bidiagonal matrix */
55: 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: DSRestoreArrayReal(ds,DS_MAT_T,&T);
60: if (l==0 && k==0) {
61: DSSetState(ds,DS_STATE_INTERMEDIATE);
62: } else {
63: DSSetState(ds,DS_STATE_RAW);
64: }
65: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
66: DSView(ds,viewer);
68: /* Solve */
69: PetscMalloc1(n,&w);
70: DSGetSlepcSC(ds,&sc);
71: sc->comparison = SlepcCompareLargestReal;
72: sc->comparisonctx = NULL;
73: sc->map = NULL;
74: sc->mapobj = NULL;
75: DSSolve(ds,w,NULL);
76: DSSort(ds,w,NULL,NULL,NULL,NULL);
77: if (extrarow) { DSUpdateExtraRow(ds); }
78: if (verbose) {
79: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
80: DSView(ds,viewer);
81: }
83: /* Print singular values */
84: PetscPrintf(PETSC_COMM_WORLD,"Computed singular values =\n");
85: for (i=0;i<n;i++) {
86: sigma = PetscRealPart(w[i]);
87: PetscViewerASCIIPrintf(viewer," %.5f\n",(double)sigma);
88: }
90: if (extrarow) {
91: /* Check that extra row is correct */
92: DSGetArrayReal(ds,DS_MAT_T,&T);
93: DSGetArray(ds,DS_MAT_U,&U);
94: d = 0.0;
95: for (i=l;i<n;i++) d += T[i+ld]-U[n-1+i*ld];
96: if (PetscAbsScalar(d)>10*PETSC_MACHINE_EPSILON) {
97: PetscPrintf(PETSC_COMM_WORLD,"Warning: there is a mismatch in the extra row of %g\n",(double)PetscAbsScalar(d));
98: }
99: DSRestoreArrayReal(ds,DS_MAT_T,&T);
100: DSRestoreArray(ds,DS_MAT_U,&U);
101: }
102: PetscFree(w);
103: DSDestroy(&ds);
104: SlepcFinalize();
105: return ierr;
106: }
108: /*TEST
110: test:
111: suffix: 1
112: requires: !single
114: test:
115: args: -l 0 -k 0
116: suffix: 2
117: requires: !single
119: test:
120: args: -extrarow
121: suffix: 3
122: requires: !single
124: TEST*/