Actual source code: shellmat.c
1: /*
2: This file contains the subroutines which implement various operations
3: of the matrix associated to the shift-and-invert technique for eigenvalue
4: problems, and also a subroutine to create it.
6: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
7: SLEPc - Scalable Library for Eigenvalue Problem Computations
8: Copyright (c) 2002-2009, Universidad Politecnica de Valencia, Spain
10: This file is part of SLEPc.
11:
12: SLEPc is free software: you can redistribute it and/or modify it under the
13: terms of version 3 of the GNU Lesser General Public License as published by
14: the Free Software Foundation.
16: SLEPc is distributed in the hope that it will be useful, but WITHOUT ANY
17: WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
18: FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
19: more details.
21: You should have received a copy of the GNU Lesser General Public License
22: along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
23: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
24: */
27: #include private/stimpl.h
31: PetscErrorCode STMatShellMult(Mat A,Vec x,Vec y)
32: {
34: ST ctx;
37: MatShellGetContext(A,(void**)&ctx);
39: MatMult(ctx->A,x,y);
40: if (ctx->sigma != 0.0) {
41: if (ctx->B) { /* y = (A - sB) x */
42: MatMult(ctx->B,x,ctx->w);
43: VecAXPY(y,-ctx->sigma,ctx->w);
44: } else { /* y = (A - sI) x */
45: VecAXPY(y,-ctx->sigma,x);
46: }
47: }
48: return(0);
49: }
53: PetscErrorCode STMatShellMultTranspose(Mat A,Vec x,Vec y)
54: {
56: ST ctx;
59: MatShellGetContext(A,(void**)&ctx);
61: MatMultTranspose(ctx->A,x,y);
62: if (ctx->sigma != 0.0) {
63: if (ctx->B) { /* y = (A - sB) x */
64: MatMultTranspose(ctx->B,x,ctx->w);
65: VecAXPY(y,-ctx->sigma,ctx->w);
66: } else { /* y = (A - sI) x */
67: VecAXPY(y,-ctx->sigma,x);
68: }
69: }
70: return(0);
71: }
75: PetscErrorCode STMatShellGetDiagonal(Mat A,Vec diag)
76: {
78: ST ctx;
79: Vec diagb;
82: MatShellGetContext(A,(void**)&ctx);
84: MatGetDiagonal(ctx->A,diag);
85: if (ctx->sigma != 0.0) {
86: if (ctx->B) {
87: VecDuplicate(diag,&diagb);
88: MatGetDiagonal(ctx->B,diagb);
89: VecAXPY(diag,-ctx->sigma,diagb);
90: VecDestroy(diagb);
91: } else {
92: VecShift(diag,-ctx->sigma);
93: }
94: }
95: return(0);
96: }
100: PetscErrorCode STMatShellCreate(ST st,Mat *mat)
101: {
103: PetscInt n, m, N, M;
104: PetscTruth hasA, hasB;
107: MatGetSize(st->A,&M,&N);
108: MatGetLocalSize(st->A,&m,&n);
109: MatCreateShell(((PetscObject)st)->comm,m,n,M,N,(void*)st,mat);
110: MatShellSetOperation(*mat,MATOP_MULT,(void(*)(void))STMatShellMult);
111: MatShellSetOperation(*mat,MATOP_MULT_TRANSPOSE,(void(*)(void))STMatShellMultTranspose);
113: MatHasOperation(st->A,MATOP_GET_DIAGONAL,&hasA);
114: if (st->B) { MatHasOperation(st->B,MATOP_GET_DIAGONAL,&hasB); }
115: if ( (hasA && !st->B) || (hasA && hasB) ) {
116: MatShellSetOperation(*mat,MATOP_GET_DIAGONAL,(void(*)(void))STMatShellGetDiagonal);
117: }
119: return(0);
120: }