Actual source code: test2.c
slepc-3.11.2 2019-07-30
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2019, 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 DSHEP.\n\n";
13: #include <slepcds.h>
15: int main(int argc,char **argv)
16: {
18: DS ds;
19: SlepcSC sc;
20: PetscScalar *A,*X,*eig;
21: PetscReal rnorm,aux;
22: PetscInt i,j,n=10,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: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type HEP - dimension %D.\n",n);
29: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
30: PetscOptionsHasName(NULL,NULL,"-extrarow",&extrarow);
32: /* Create DS object */
33: DSCreate(PETSC_COMM_WORLD,&ds);
34: DSSetType(ds,DSHEP);
35: DSSetFromOptions(ds);
36: ld = n+2; /* test leading dimension larger than n */
37: DSAllocate(ds,ld);
38: DSSetDimensions(ds,n,0,0,0);
39: DSSetExtraRow(ds,extrarow);
41: /* Set up viewer */
42: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
43: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
44: DSView(ds,viewer);
45: PetscViewerPopFormat(viewer);
46: if (verbose) {
47: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
48: }
50: /* Fill with a symmetric Toeplitz matrix */
51: DSGetArray(ds,DS_MAT_A,&A);
52: for (i=0;i<n;i++) A[i+i*ld]=2.0;
53: for (j=1;j<3;j++) {
54: for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
55: }
56: if (extrarow) { A[n+(n-2)*ld]=1.0; A[n+(n-1)*ld]=1.0; }
57: DSRestoreArray(ds,DS_MAT_A,&A);
58: DSSetState(ds,DS_STATE_RAW);
59: if (verbose) {
60: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
61: DSView(ds,viewer);
62: }
64: /* Solve */
65: PetscMalloc1(n,&eig);
66: DSGetSlepcSC(ds,&sc);
67: sc->comparison = SlepcCompareLargestMagnitude;
68: sc->comparisonctx = NULL;
69: sc->map = NULL;
70: sc->mapobj = NULL;
71: DSSolve(ds,eig,NULL);
72: DSSort(ds,eig,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 eigenvalues */
80: PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
81: for (i=0;i<n;i++) {
82: PetscViewerASCIIPrintf(viewer," %.5f\n",(double)PetscRealPart(eig[i]));
83: }
85: /* Eigenvectors */
86: j = 2;
87: DSVectors(ds,DS_MAT_X,&j,&rnorm); /* third eigenvector */
88: PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 3rd vector = %.3f\n",(double)rnorm);
89: DSVectors(ds,DS_MAT_X,NULL,NULL); /* all eigenvectors */
90: j = 0;
91: rnorm = 0.0;
92: DSGetArray(ds,DS_MAT_X,&X);
93: for (i=0;i<n;i++) {
94: aux = PetscAbsScalar(X[i+j*ld]);
95: rnorm += aux*aux;
96: }
97: DSRestoreArray(ds,DS_MAT_X,&X);
98: rnorm = PetscSqrtReal(rnorm);
99: PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
100: if (verbose) {
101: PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
102: DSView(ds,viewer);
103: }
105: PetscFree(eig);
106: DSDestroy(&ds);
107: SlepcFinalize();
108: return ierr;
109: }
111: /*TEST
113: test:
114: suffix: 1
115: args: -n 12 -ds_method {{0 1 2}}
116: filter: grep -v "solving the problem"
117: requires: !single
119: TEST*/