Actual source code: test20.c
slepc-3.17.1 2022-04-11
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;
24: SlepcInitialize(&argc,&argv,(char*)0,help);
25: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
26: PetscPrintf(PETSC_COMM_WORLD,"Solve a Dense System of type GNHEP - dimension %" PetscInt_FMT ".\n",n);
27: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
29: /* Create DS object */
30: DSCreate(PETSC_COMM_WORLD,&ds);
31: DSSetType(ds,DSGNHEP);
32: DSSetFromOptions(ds);
33: ld = n+2; /* test leading dimension larger than n */
34: DSAllocate(ds,ld);
35: DSSetDimensions(ds,n,0,0);
37: /* Set up viewer */
38: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&viewer);
39: PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO_DETAIL);
40: DSView(ds,viewer);
41: PetscViewerPopFormat(viewer);
42: if (verbose) PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_MATLAB);
44: /* Fill A,B with upper quasi-triangular matrices */
45: DSGetArray(ds,DS_MAT_A,&A);
46: DSGetArray(ds,DS_MAT_B,&B);
47: PetscArrayzero(A,ld*n);
48: for (i=0;i<n;i++) A[i+i*ld]=2.0;
49: for (j=1;j<3;j++) {
50: for (i=0;i<n-j;i++) A[i+(i+j)*ld]=0.001;
51: }
52: PetscArrayzero(B,ld*n);
53: for (i=0;i<n;i++) B[i+i*ld]=1.0;
54: B[1+0*ld]=B[0+1*ld]=PETSC_MACHINE_EPSILON;
55: for (i=1;i<n;i+=3) {
56: A[i+(i-1)*ld]=-A[(i-1)+i*ld];
57: }
58: DSRestoreArray(ds,DS_MAT_A,&A);
59: DSRestoreArray(ds,DS_MAT_B,&B);
60: DSSetState(ds,DS_STATE_INTERMEDIATE);
62: if (verbose) {
63: PetscPrintf(PETSC_COMM_WORLD,"Initial - - - - - - - - -\n");
64: DSView(ds,viewer);
65: }
67: /* Eigenvectors */
68: j = 0;
69: DSVectors(ds,DS_MAT_X,&j,&rnorm); /* first eigenvector */
70: PetscPrintf(PETSC_COMM_WORLD,"Value of rnorm for 2nd vector = %.3f\n",(double)rnorm);
71: DSVectors(ds,DS_MAT_X,NULL,NULL); /* all eigenvectors */
72: j = 0;
73: rnorm = 0.0;
74: DSGetArray(ds,DS_MAT_X,&X);
75: for (i=0;i<n;i++) {
76: #if defined(PETSC_USE_COMPLEX)
77: aux = PetscAbsScalar(X[i+j*ld]);
78: #else
79: aux = SlepcAbsEigenvalue(X[i+j*ld],X[i+(j+1)*ld]);
80: #endif
81: rnorm += aux*aux;
82: }
83: DSRestoreArray(ds,DS_MAT_X,&X);
84: rnorm = PetscSqrtReal(rnorm);
85: PetscPrintf(PETSC_COMM_WORLD,"Norm of 1st columns = %.3f\n",(double)rnorm);
86: if (verbose) {
87: PetscPrintf(PETSC_COMM_WORLD,"After vectors - - - - - - - - -\n");
88: DSView(ds,viewer);
89: }
91: DSDestroy(&ds);
92: SlepcFinalize();
93: return 0;
94: }
96: /*TEST
98: test:
99: suffix: 1
101: TEST*/