Actual source code: test1.c
slepc-3.8.3 2018-04-03
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2017, 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[] = "Tests B-orthonormality of eigenvectors in a GHEP problem.\n\n";
13: #include <slepceps.h>
15: int main(int argc,char **argv)
16: {
17: Mat A,B; /* matrices */
18: EPS eps; /* eigenproblem solver context */
19: ST st;
20: Vec *X,v;
21: PetscReal lev,tol=1000*PETSC_MACHINE_EPSILON;
22: PetscInt N,n=45,m,Istart,Iend,II,i,j,nconv;
23: PetscBool flag;
24: EPSPowerShiftType variant;
25: PetscErrorCode ierr;
27: SlepcInitialize(&argc,&argv,(char*)0,help);if (ierr) return ierr;
28: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
29: PetscOptionsGetInt(NULL,NULL,"-m",&m,&flag);
30: if (!flag) m=n;
31: N = n*m;
32: PetscPrintf(PETSC_COMM_WORLD,"\nGeneralized Symmetric Eigenproblem, N=%D (%Dx%D grid)\n\n",N,n,m);
34: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
35: Compute the matrices that define the eigensystem, Ax=kBx
36: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
38: MatCreate(PETSC_COMM_WORLD,&A);
39: MatSetSizes(A,PETSC_DECIDE,PETSC_DECIDE,N,N);
40: MatSetFromOptions(A);
41: MatSetUp(A);
43: MatCreate(PETSC_COMM_WORLD,&B);
44: MatSetSizes(B,PETSC_DECIDE,PETSC_DECIDE,N,N);
45: MatSetFromOptions(B);
46: MatSetUp(B);
48: MatGetOwnershipRange(A,&Istart,&Iend);
49: for (II=Istart;II<Iend;II++) {
50: i = II/n; j = II-i*n;
51: if (i>0) { MatSetValue(A,II,II-n,-1.0,INSERT_VALUES); }
52: if (i<m-1) { MatSetValue(A,II,II+n,-1.0,INSERT_VALUES); }
53: if (j>0) { MatSetValue(A,II,II-1,-1.0,INSERT_VALUES); }
54: if (j<n-1) { MatSetValue(A,II,II+1,-1.0,INSERT_VALUES); }
55: MatSetValue(A,II,II,4.0,INSERT_VALUES);
56: MatSetValue(B,II,II,2.0/PetscLogScalar(II+2),INSERT_VALUES);
57: }
59: MatAssemblyBegin(A,MAT_FINAL_ASSEMBLY);
60: MatAssemblyEnd(A,MAT_FINAL_ASSEMBLY);
61: MatAssemblyBegin(B,MAT_FINAL_ASSEMBLY);
62: MatAssemblyEnd(B,MAT_FINAL_ASSEMBLY);
63: MatCreateVecs(B,&v,NULL);
65: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
66: Create the eigensolver and set various options
67: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
69: EPSCreate(PETSC_COMM_WORLD,&eps);
70: EPSSetOperators(eps,A,B);
71: EPSSetProblemType(eps,EPS_GHEP);
72: EPSSetTolerances(eps,tol,PETSC_DEFAULT);
73: EPSSetConvergenceTest(eps,EPS_CONV_NORM);
74: EPSSetFromOptions(eps);
76: /* illustrate how to extract parameters from specific solver types */
77: PetscObjectTypeCompare((PetscObject)eps,EPSPOWER,&flag);
78: if (flag) {
79: EPSGetST(eps,&st);
80: PetscObjectTypeCompare((PetscObject)st,STSHIFT,&flag);
81: if (flag) {
82: EPSPowerGetShiftType(eps,&variant);
83: PetscPrintf(PETSC_COMM_WORLD,"Type of shifts used during power iteration: %s\n",EPSPowerShiftTypes[variant]);
84: }
85: }
87: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
88: Solve the eigensystem
89: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
91: EPSSolve(eps);
93: /* - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
94: Display solution and clean up
95: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - */
97: EPSGetTolerances(eps,&tol,NULL);
98: EPSErrorView(eps,EPS_ERROR_BACKWARD,NULL);
99: EPSGetConverged(eps,&nconv);
100: if (nconv>1) {
101: VecDuplicateVecs(v,nconv,&X);
102: for (i=0;i<nconv;i++) {
103: EPSGetEigenvector(eps,i,X[i],NULL);
104: }
105: VecCheckOrthogonality(X,nconv,NULL,nconv,B,NULL,&lev);
106: if (lev<10*tol) {
107: PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality below the tolerance\n");
108: } else {
109: PetscPrintf(PETSC_COMM_WORLD,"Level of orthogonality: %g\n",(double)lev);
110: }
111: VecDestroyVecs(nconv,&X);
112: }
114: EPSDestroy(&eps);
115: MatDestroy(&A);
116: MatDestroy(&B);
117: VecDestroy(&v);
118: SlepcFinalize();
119: return ierr;
120: }