Actual source code: test9.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 DSGHEP.\n\n";
13: #include <slepcds.h>
15: /*
16: Compute the norm of the j-th column of matrix mat in ds
17: */
18: PetscErrorCode ComputeNorm(DS ds,DSMatType mat,PetscInt j,PetscReal *onrm)
19: {
21: PetscScalar *X;
22: PetscReal aux,nrm=0.0;
23: PetscInt i,n,ld;
26: DSGetLeadingDimension(ds,&ld);
27: DSGetDimensions(ds,&n,NULL,NULL,NULL,NULL);
28: DSGetArray(ds,mat,&X);
29: for (i=0;i<n;i++) {
30: aux = PetscAbsScalar(X[i+j*ld]);
31: nrm += aux*aux;
32: }
33: DSRestoreArray(ds,mat,&X);
34: *onrm = PetscSqrtReal(nrm);
35: return(0);
36: }
38: int main(int argc,char **argv)
39: {
41: DS ds;
42: SlepcSC sc;
43: PetscReal re;
44: PetscScalar *A,*B,*eig;
45: PetscReal nrm;
46: PetscInt i,j,n=10,ld;
47: PetscViewer viewer;
48: PetscBool verbose;
50: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
51: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
52: PetscPrintf(PETSC_COMM_WORLD,"Solve a System of type GHEP - dimension %D.\n",n);
53: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
55: /* Create DS object */
56: DSCreate(PETSC_COMM_WORLD,&ds);
57: DSSetType(ds,DSGHEP);
58: DSSetFromOptions(ds);
59: ld = n+2; /* test leading dimension larger than n */
60: DSAllocate(ds,ld);
61: DSSetDimensions(ds,n,0,0,0);
63: /* Set up viewer */
64: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
65: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
66: DSView(ds,viewer);
67: PetscViewerPopFormat(viewer);
68: if (verbose) {
69: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
70: }
72: /* Fill with a symmetric Toeplitz matrix */
73: DSGetArray(ds,DS_MAT_A,&A);
74: DSGetArray(ds,DS_MAT_B,&B);
75: for (i=0;i<n;i++) A[i+i*ld]=2.0;
76: for (j=1;j<3;j++) {
77: for (i=0;i<n-j;i++) { A[i+(i+j)*ld]=1.0; A[(i+j)+i*ld]=1.0; }
78: }
79: for (j=1;j<3;j++) { A[0+j*ld]=-1.0*(j+2); A[j+0*ld]=-1.0*(j+2); }
80: /* Diagonal matrix */
81: for (i=0;i<n;i++) B[i+i*ld]=0.1*(i+1);
82: DSRestoreArray(ds,DS_MAT_A,&A);
83: DSRestoreArray(ds,DS_MAT_B,&B);
84: DSSetState(ds,DS_STATE_RAW);
85: if (verbose) {
86: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
87: DSView(ds,viewer);
88: }
90: /* Solve */
91: PetscMalloc1(n,&eig);
92: PetscNew(&sc);
93: sc->comparison = SlepcCompareLargestMagnitude;
94: sc->comparisonctx = NULL;
95: sc->map = NULL;
96: sc->mapobj = NULL;
97: DSSetSlepcSC(ds,sc);
98: DSSolve(ds,eig,NULL);
99: DSSort(ds,eig,NULL,NULL,NULL,NULL);
100: if (verbose) {
101: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
102: DSView(ds,viewer);
103: }
105: /* Print eigenvalues */
106: PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
107: for (i=0;i<n;i++) {
108: re = PetscRealPart(eig[i]);
109: PetscViewerASCIIPrintf(viewer," %.5f\n",(double)re);
110: }
112: /* Eigenvectors */
113: DSVectors(ds,DS_MAT_X,NULL,NULL); /* all eigenvectors */
114: ComputeNorm(ds,DS_MAT_X,0,&nrm);
115: PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)nrm);
116: if (verbose) {
117: PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
118: DSView(ds,viewer);
119: }
121: PetscFree(eig);
122: PetscFree(sc);
123: DSDestroy(&ds);
124: SlepcFinalize();
125: return ierr;
126: }
128: /*TEST
130: test:
131: suffix: 1
132: requires: !single
134: TEST*/