Actual source code: test2.c
slepc-3.18.2 2023-01-26
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 DSHEP.\n\n";
13: #include <slepcds.h>
15: int main(int argc,char **argv)
16: {
17: DS ds;
18: SlepcSC sc;
19: PetscScalar *A,*X,*Q,*eig,d;
20: PetscReal rnorm,aux;
21: PetscInt i,j,n=10,ld;
22: PetscViewer viewer;
23: PetscBool verbose,extrarow;
26: SlepcInitialize(&argc,&argv,(char*)0,help);
27: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
28: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type HEP - dimension %" PetscInt_FMT ".\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);
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) PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
48: /* Fill with a symmetric Toeplitz matrix */
49: DSGetArray(ds,DS_MAT_A,&A);
50: for (i=0;i<n;i++) A[i+i*ld]=2.0;
51: for (j=1;j<3;j++) {
52: for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
53: }
54: if (extrarow) { A[n+(n-2)*ld]=1.0; A[n+(n-1)*ld]=1.0; }
55: DSRestoreArray(ds,DS_MAT_A,&A);
56: DSSetState(ds,DS_STATE_RAW);
57: if (verbose) {
58: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
59: DSView(ds,viewer);
60: }
62: /* Solve */
63: PetscMalloc1(n,&eig);
64: DSGetSlepcSC(ds,&sc);
65: sc->comparison = SlepcCompareLargestMagnitude;
66: sc->comparisonctx = NULL;
67: sc->map = NULL;
68: sc->mapobj = NULL;
69: DSSolve(ds,eig,NULL);
70: DSSort(ds,eig,NULL,NULL,NULL,NULL);
71: if (extrarow) DSUpdateExtraRow(ds);
72: if (verbose) {
73: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
74: DSView(ds,viewer);
75: }
77: /* Print eigenvalues */
78: PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
79: for (i=0;i<n;i++) PetscViewerASCIIPrintf(viewer," %.5f\n",(double)PetscRealPart(eig[i]));
81: if (extrarow) {
82: /* Check that extra row is correct */
83: DSGetArray(ds,DS_MAT_A,&A);
84: DSGetArray(ds,DS_MAT_Q,&Q);
85: d = 0.0;
86: for (i=0;i<n;i++) d += A[n+i*ld]-Q[n-2+i*ld]-Q[n-1+i*ld];
87: 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));
88: DSRestoreArray(ds,DS_MAT_A,&A);
89: DSRestoreArray(ds,DS_MAT_Q,&Q);
90: }
92: /* Eigenvectors */
93: j = 2;
94: DSVectors(ds,DS_MAT_X,&j,&rnorm); /* third eigenvector */
95: PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 3rd vector = %.3f\n",(double)rnorm);
96: DSVectors(ds,DS_MAT_X,NULL,NULL); /* all eigenvectors */
97: j = 0;
98: rnorm = 0.0;
99: DSGetArray(ds,DS_MAT_X,&X);
100: for (i=0;i<n;i++) {
101: aux = PetscAbsScalar(X[i+j*ld]);
102: rnorm += aux*aux;
103: }
104: DSRestoreArray(ds,DS_MAT_X,&X);
105: rnorm = PetscSqrtReal(rnorm);
106: PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
107: if (verbose) {
108: PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
109: DSView(ds,viewer);
110: }
112: PetscFree(eig);
113: DSDestroy(&ds);
114: SlepcFinalize();
115: return 0;
116: }
118: /*TEST
120: testset:
121: args: -n 12 -ds_method {{0 1 2}}
122: filter: grep -v "solving the problem" | sed -e "s/extrarow//"
123: output_file: output/test2_1.out
124: requires: !single
125: test:
126: suffix: 1
127: test:
128: suffix: 2
129: args: -extrarow
131: TEST*/