Actual source code: test20.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 DSGNHEP with upper quasi-triangular matrix pair.\n\n";
13: #include <slepcds.h>
15: int main(int argc,char **argv)
16: {
17: DS ds;
18: PetscScalar *A,*B,*X;
19: PetscReal rnorm,aux;
20: PetscInt i,j,n=10,ld;
21: PetscViewer viewer;
22: PetscBool verbose;
25: SlepcInitialize(&argc,&argv,(char*)0,help);
26: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
27: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GNHEP - dimension %" PetscInt_FMT ".\n",n);
28: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
30: /* Create DS object */
31: DSCreate(PETSC_COMM_WORLD,&ds);
32: DSSetType(ds,DSGNHEP);
33: DSSetFromOptions(ds);
34: ld = n+2; /* test leading dimension larger than n */
35: DSAllocate(ds,ld);
36: DSSetDimensions(ds,n,0,0);
38: /* Set up viewer */
39: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
40: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
41: DSView(ds,viewer);
42: PetscViewerPopFormat(viewer);
43: if (verbose) PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
45: /* Fill A,B with upper quasi-triangular matrices */
46: DSGetArray(ds,DS_MAT_A,&A);
47: DSGetArray(ds,DS_MAT_B,&B);
48: PetscArrayzero(A,ld*n);
49: for (i=0;i<n;i++) A[i+i*ld]=2.0;
50: for (j=1;j<3;j++) {
51: for (i=0;i<n-j;i++) A[i+(i+j)*ld]=0.001;
52: }
53: PetscArrayzero(B,ld*n);
54: for (i=0;i<n;i++) B[i+i*ld]=1.0;
55: B[1+0*ld]=B[0+1*ld]=PETSC_MACHINE_EPSILON;
56: for (i=1;i<n;i+=3) {
57: A[i+(i-1)*ld]=-A[(i-1)+i*ld];
58: }
59: DSRestoreArray(ds,DS_MAT_A,&A);
60: DSRestoreArray(ds,DS_MAT_B,&B);
61: DSSetState(ds,DS_STATE_INTERMEDIATE);
63: if (verbose) {
64: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
65: DSView(ds,viewer);
66: }
68: /* Eigenvectors */
69: j = 0;
70: DSVectors(ds,DS_MAT_X,&j,&rnorm); /* first eigenvector */
71: PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm);
72: DSVectors(ds,DS_MAT_X,NULL,NULL); /* all eigenvectors */
73: j = 0;
74: rnorm = 0.0;
75: DSGetArray(ds,DS_MAT_X,&X);
76: for (i=0;i<n;i++) {
77: #if defined(PETSC_USE_COMPLEX)
78: aux = PetscAbsScalar(X[i+j*ld]);
79: #else
80: aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
81: #endif
82: rnorm += aux*aux;
83: }
84: DSRestoreArray(ds,DS_MAT_X,&X);
85: rnorm = PetscSqrtReal(rnorm);
86: PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st columns = %.3f\n",(double)rnorm);
87: if (verbose) {
88: PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
89: DSView(ds,viewer);
90: }
92: DSDestroy(&ds);
93: SlepcFinalize();
94: return 0;
95: }
97: /*TEST
99: test:
100: suffix: 1
102: TEST*/