Actual source code: test4.c
slepc-3.18.1 2022-11-02
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 DSGNHEP.\n\n";
13: #include <slepcds.h>
15: int main(int argc,char **argv)
16: {
17: DS ds;
18: SlepcSC sc;
19: PetscScalar *A,*B,*X,*wr,*wi;
20: PetscReal re,im,rnorm,aux;
21: PetscInt i,j,n=10,ld;
22: PetscViewer viewer;
23: PetscBool verbose;
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 GNHEP - dimension %" PetscInt_FMT ".\n",n);
29: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
31: /* Create DS object */
32: DSCreate(PETSC_COMM_WORLD,&ds);
33: DSSetType(ds,DSGNHEP);
34: DSSetFromOptions(ds);
35: ld = n+2; /* test leading dimension larger than n */
36: DSAllocate(ds,ld);
37: DSSetDimensions(ds,n,0,0);
39: /* Set up viewer */
40: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
41: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
42: DSView(ds,viewer);
43: PetscViewerPopFormat(viewer);
44: if (verbose) PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
46: /* Fill A with Grcar matrix */
47: DSGetArray(ds,DS_MAT_A,&A);
48: PetscArrayzero(A,ld*n);
49: for (i=1;i<n;i++) A[i+(i-1)*ld]=-1.0;
50: for (j=0;j<4;j++) {
51: for (i=0;i<n-j;i++) A[i+(i+j)*ld]=1.0;
52: }
53: DSRestoreArray(ds,DS_MAT_A,&A);
54: /* Fill B with an upper triangular matrix */
55: DSGetArray(ds,DS_MAT_B,&B);
56: PetscArrayzero(B,ld*n);
57: B[0+0*ld]=-1.0;
58: B[0+1*ld]=2.0;
59: for (i=1;i<n;i++) B[i+i*ld]=1.0;
60: DSRestoreArray(ds,DS_MAT_B,&B);
62: if (verbose) {
63: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
64: DSView(ds,viewer);
65: }
67: /* Solve */
68: PetscMalloc2(n,&wr,n,&wi);
69: DSGetSlepcSC(ds,&sc);
70: sc->comparison = SlepcCompareLargestMagnitude;
71: sc->comparisonctx = NULL;
72: sc->map = NULL;
73: sc->mapobj = NULL;
74: DSSolve(ds,wr,wi);
75: DSSort(ds,wr,wi,NULL,NULL,NULL);
76: if (verbose) {
77: PetscPrintf(PETSC_COMM_WORLD,"After solve - - - - - - - - -\n");
78: DSView(ds,viewer);
79: }
81: /* Print eigenvalues */
82: PetscPrintf(PETSC_COMM_WORLD,"Computed eigenvalues =\n");
83: for (i=0;i<n;i++) {
84: #if defined(PETSC_USE_COMPLEX)
85: re = PetscRealPart(wr[i]);
86: im = PetscImaginaryPart(wr[i]);
87: #else
88: re = wr[i];
89: im = wi[i];
90: #endif
91: if (PetscAbs(im)<1e-10) PetscViewerASCIIPrintf(viewer," %.5f\n",(double)re);
92: else PetscViewerASCIIPrintf(viewer," %.5f%+.5fi\n",(double)re,(double)im);
93: }
95: /* Eigenvectors */
96: j = 1;
97: DSVectors(ds,DS_MAT_X,&j,&rnorm); /* second eigenvector */
98: PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm);
99: DSVectors(ds,DS_MAT_X,NULL,NULL); /* all eigenvectors */
100: j = 0;
101: rnorm = 0.0;
102: DSGetArray(ds,DS_MAT_X,&X);
103: for (i=0;i<n;i++) {
104: #if defined(PETSC_USE_COMPLEX)
105: aux = PetscAbsScalar(X[i+j*ld]);
106: #else
107: if (PetscAbs(wi[j])==0.0) aux = PetscAbsScalar(X[i+j*ld]);
108: else aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
109: #endif
110: rnorm += aux*aux;
111: }
112: DSRestoreArray(ds,DS_MAT_X,&X);
113: rnorm = PetscSqrtReal(rnorm);
114: PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st vector = %.3f\n",(double)rnorm);
115: if (verbose) {
116: PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
117: DSView(ds,viewer);
118: }
120: PetscFree2(wr,wi);
121: DSDestroy(&ds);
122: SlepcFinalize();
123: return 0;
124: }
126: /*TEST
128: test:
129: suffix: 1
130: filter: sed -e "s/[+-]\([0-9]\.[0-9]*i\)/+-\\1/" | sed -e "s/+-0\.0*i//"
132: TEST*/