Actual source code: test8.c
slepc-3.7.1 2016-05-27
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain
6: This file is part of SLEPc.
8: SLEPc is free software: you can redistribute it and/or modify it under the
9: terms of version 3 of the GNU Lesser General Public License as published by
10: the Free Software Foundation.
12: SLEPc is distributed in the hope that it will be useful, but WITHOUT ANY
13: WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
14: FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
15: more details.
17: You should have received a copy of the GNU Lesser General Public License
18: along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
19: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
20: */
22: static char help[] = "Test BV orthogonalization with selected columns.\n\n";
24: #include <slepcbv.h>
28: int main(int argc,char **argv)
29: {
31: BV X;
32: Vec v,t,z;
33: PetscInt i,j,n=20,k=8;
34: PetscViewer view;
35: PetscBool verbose,*which;
36: PetscReal norm;
37: PetscScalar alpha,*pz;
39: SlepcInitialize(&argc,&argv,(char*)0,help);
40: PetscOptionsGetInt(NULL,NULL,"-n",&n,NULL);
41: PetscOptionsGetInt(NULL,NULL,"-k",&k,NULL);
42: PetscOptionsHasName(NULL,NULL,"-verbose",&verbose);
43: PetscPrintf(PETSC_COMM_WORLD,"Test BV orthogonalization with selected columns of length %D.\n",n);
45: /* Create template vector */
46: VecCreate(PETSC_COMM_WORLD,&t);
47: VecSetSizes(t,PETSC_DECIDE,n);
48: VecSetFromOptions(t);
50: /* Create BV object X */
51: BVCreate(PETSC_COMM_WORLD,&X);
52: PetscObjectSetName((PetscObject)X,"X");
53: BVSetSizesFromVec(X,t,k);
54: BVSetOrthogonalization(X,BV_ORTHOG_MGS,BV_ORTHOG_REFINE_IFNEEDED,PETSC_DEFAULT,BV_ORTHOG_BLOCK_GS);
55: BVSetFromOptions(X);
57: /* Set up viewer */
58: PetscViewerASCIIGetStdout(PETSC_COMM_WORLD,&view);
59: if (verbose) {
60: PetscViewerPushFormat(view,PETSC_VIEWER_ASCII_MATLAB);
61: }
63: /* Fill X entries */
64: for (j=0;j<k;j++) {
65: BVGetColumn(X,j,&v);
66: VecSet(v,0.0);
67: for (i=0;i<=n/2;i++) {
68: if (i+j<n) {
69: alpha = (3.0*i+j-2)/(2*(i+j+1));
70: VecSetValue(v,i+j,alpha,INSERT_VALUES);
71: }
72: }
73: VecAssemblyBegin(v);
74: VecAssemblyEnd(v);
75: BVRestoreColumn(X,j,&v);
76: }
77: if (verbose) {
78: BVView(X,view);
79: }
81: /* Orthonormalize first k-1 columns */
82: for (j=0;j<k-1;j++) {
83: BVOrthogonalizeColumn(X,j,NULL,&norm,NULL);
84: alpha = 1.0/norm;
85: BVScaleColumn(X,j,alpha);
86: }
87: if (verbose) {
88: BVView(X,view);
89: }
91: /* Select odd columns and orthogonalize last column against those only */
92: PetscMalloc1(k,&which);
93: for (i=0;i<k;i++) which[i] = (i%2)? PETSC_TRUE: PETSC_FALSE;
94: BVOrthogonalizeSomeColumn(X,k-1,which,NULL,NULL,NULL);
95: PetscFree(which);
96: if (verbose) {
97: BVView(X,view);
98: }
100: /* Check orthogonality */
101: PetscPrintf(PETSC_COMM_WORLD,"Orthogonalization coefficients:\n");
102: VecCreateSeq(PETSC_COMM_SELF,k-1,&z);
103: PetscObjectSetName((PetscObject)z,"z");
104: VecGetArray(z,&pz);
105: BVDotColumn(X,k-1,pz);
106: for (i=0;i<k-1;i++) {
107: if (PetscAbsScalar(pz[i])<PETSC_MACHINE_EPSILON) pz[i]=0.0;
108: }
109: VecRestoreArray(z,&pz);
110: VecView(z,view);
111: VecDestroy(&z);
113: BVDestroy(&X);
114: VecDestroy(&t);
115: SlepcFinalize();
116: return ierr;
117: }