Actual source code: stsolve.c
1: /*
2: The ST (spectral transformation) interface routines, callable by users.
4: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
5: SLEPc - Scalable Library for Eigenvalue Problem Computations
6: Copyright (c) 2002-2011, Universitat Politecnica de Valencia, Spain
8: This file is part of SLEPc.
9:
10: SLEPc is free software: you can redistribute it and/or modify it under the
11: terms of version 3 of the GNU Lesser General Public License as published by
12: the Free Software Foundation.
14: SLEPc is distributed in the hope that it will be useful, but WITHOUT ANY
15: WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
16: FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
17: more details.
19: You should have received a copy of the GNU Lesser General Public License
20: along with SLEPc. If not, see <http://www.gnu.org/licenses/>.
21: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
22: */
24: #include <private/stimpl.h> /*I "slepcst.h" I*/
28: /*@
29: STApply - Applies the spectral transformation operator to a vector, for
30: instance (A - sB)^-1 B in the case of the shift-and-invert tranformation
31: and generalized eigenproblem.
33: Collective on ST and Vec
35: Input Parameters:
36: + st - the spectral transformation context
37: - x - input vector
39: Output Parameter:
40: . y - output vector
42: Level: developer
44: .seealso: STApplyTranspose()
45: @*/
46: PetscErrorCode STApply(ST st,Vec x,Vec y)
47: {
54: if (x == y) SETERRQ(((PetscObject)st)->comm,PETSC_ERR_ARG_IDN,"x and y must be different vectors");
56: if (!st->setupcalled) { STSetUp(st); }
58: if (!st->ops->apply) SETERRQ(((PetscObject)st)->comm,PETSC_ERR_SUP,"ST does not have apply");
59: PetscLogEventBegin(ST_Apply,st,x,y,0);
60: st->applys++;
61: if (st->D) { /* with balancing */
62: VecPointwiseDivide(st->wb,x,st->D);
63: (*st->ops->apply)(st,st->wb,y);
64: VecPointwiseMult(y,y,st->D);
65: }
66: else {
67: (*st->ops->apply)(st,x,y);
68: }
69: PetscLogEventEnd(ST_Apply,st,x,y,0);
70: return(0);
71: }
75: /*@
76: STGetBilinearForm - Returns the matrix used in the bilinear form with a
77: generalized problem with semi-definite B.
79: Not collective, though a parallel Mat may be returned
81: Input Parameters:
82: . st - the spectral transformation context
84: Output Parameter:
85: . B - output matrix
87: Notes:
88: The output matrix B must be destroyed after use. It will be PETSC_NULL in
89: case of standard eigenproblems.
90:
91: Level: developer
92: @*/
93: PetscErrorCode STGetBilinearForm(ST st,Mat *B)
94: {
100: (*st->ops->getbilinearform)(st,B);
101: return(0);
102: }
106: PetscErrorCode STGetBilinearForm_Default(ST st,Mat *B)
107: {
111: *B = st->B;
112: if (*B) {
113: PetscObjectReference((PetscObject)*B);
114: }
115: return(0);
116: }
120: /*@
121: STApplyTranspose - Applies the transpose of the operator to a vector, for
122: instance B^T(A - sB)^-T in the case of the shift-and-invert tranformation
123: and generalized eigenproblem.
125: Collective on ST and Vec
127: Input Parameters:
128: + st - the spectral transformation context
129: - x - input vector
131: Output Parameter:
132: . y - output vector
134: Level: developer
136: .seealso: STApply()
137: @*/
138: PetscErrorCode STApplyTranspose(ST st,Vec x,Vec y)
139: {
146: if (x == y) SETERRQ(((PetscObject)st)->comm,PETSC_ERR_ARG_IDN,"x and y must be different vectors");
148: if (!st->setupcalled) { STSetUp(st); }
150: if (!st->ops->applytrans) SETERRQ(((PetscObject)st)->comm,PETSC_ERR_SUP,"ST does not have applytrans");
151: PetscLogEventBegin(ST_ApplyTranspose,st,x,y,0);
152: st->applys++;
153: if (st->D) { /* with balancing */
154: VecPointwiseMult(st->wb,x,st->D);
155: (*st->ops->applytrans)(st,st->wb,y);
156: VecPointwiseDivide(y,y,st->D);
157: }
158: else {
159: (*st->ops->applytrans)(st,x,y);
160: }
161: PetscLogEventEnd(ST_ApplyTranspose,st,x,y,0);
162: return(0);
163: }
167: /*@
168: STComputeExplicitOperator - Computes the explicit operator associated
169: to the eigenvalue problem with the specified spectral transformation.
171: Collective on ST
173: Input Parameter:
174: . st - the spectral transform context
176: Output Parameter:
177: . mat - the explicit operator
179: Notes:
180: This routine builds a matrix containing the explicit operator. For
181: example, in generalized problems with shift-and-invert spectral
182: transformation the result would be matrix (A - s B)^-1 B.
184: This computation is done by applying the operator to columns of the
185: identity matrix. Note that the result is a dense matrix.
187: Level: advanced
189: .seealso: STApply()
190: @*/
191: PetscErrorCode STComputeExplicitOperator(ST st,Mat *mat)
192: {
193: PetscErrorCode ierr;
194: Vec in,out;
195: PetscInt i,M,m,*rows,start,end;
196: const PetscScalar *array;
197: PetscScalar one = 1.0;
203: MatGetVecs(st->A,&in,&out);
204: VecGetSize(out,&M);
205: VecGetLocalSize(out,&m);
206: VecGetOwnershipRange(out,&start,&end);
207: PetscMalloc(m*sizeof(PetscInt),&rows);
208: for (i=0; i<m; i++) rows[i] = start + i;
210: MatCreateMPIDense(((PetscObject)st)->comm,m,m,M,M,PETSC_NULL,mat);
212: for (i=0; i<M; i++) {
213: VecSet(in,0.0);
214: VecSetValues(in,1,&i,&one,INSERT_VALUES);
215: VecAssemblyBegin(in);
216: VecAssemblyEnd(in);
218: STApply(st,in,out);
219:
220: VecGetArrayRead(out,&array);
221: MatSetValues(*mat,m,rows,1,&i,array,INSERT_VALUES);
222: VecRestoreArrayRead(out,&array);
223: }
224: PetscFree(rows);
225: VecDestroy(&in);
226: VecDestroy(&out);
227: MatAssemblyBegin(*mat,MAT_FINAL_ASSEMBLY);
228: MatAssemblyEnd(*mat,MAT_FINAL_ASSEMBLY);
229: return(0);
230: }
234: /*@
235: STSetUp - Prepares for the use of a spectral transformation.
237: Collective on ST
239: Input Parameter:
240: . st - the spectral transformation context
242: Level: advanced
244: .seealso: STCreate(), STApply(), STDestroy()
245: @*/
246: PetscErrorCode STSetUp(ST st)
247: {
248: PetscInt n,k;
253: if (!st->A) {SETERRQ(((PetscObject)st)->comm,PETSC_ERR_ARG_WRONGSTATE,"Matrix must be set first");}
254: if (st->setupcalled) return(0);
255: PetscInfo(st,"Setting up new ST\n");
256: PetscLogEventBegin(ST_SetUp,st,0,0,0);
257: if (!((PetscObject)st)->type_name) {
258: STSetType(st,STSHIFT);
259: }
260: VecDestroy(&st->w);
261: MatGetVecs(st->A,&st->w,PETSC_NULL);
262: if (st->D) {
263: MatGetLocalSize(st->A,PETSC_NULL,&n);
264: VecGetLocalSize(st->D,&k);
265: if (n != k) SETERRQ2(PETSC_COMM_SELF,PETSC_ERR_ARG_SIZ,"Balance matrix has wrong dimension %D (should be %D)",k,n);
266: VecDestroy(&st->wb);
267: VecDuplicate(st->D,&st->wb);
268: }
269: if (st->ops->setup) { (*st->ops->setup)(st); }
270: st->setupcalled = 1;
271: PetscLogEventEnd(ST_SetUp,st,0,0,0);
272: return(0);
273: }
277: /*@
278: STPostSolve - Optional post-solve phase, intended for any actions that must
279: be performed on the ST object after the eigensolver has finished.
281: Collective on ST
283: Input Parameters:
284: . st - the spectral transformation context
286: Level: developer
288: .seealso: EPSSolve()
289: @*/
290: PetscErrorCode STPostSolve(ST st)
291: {
296: if (st->ops->postsolve) {
297: (*st->ops->postsolve)(st);
298: }
299: return(0);
300: }
304: /*@
305: STBackTransform - Back-transformation phase, intended for
306: spectral transformations which require to transform the computed
307: eigenvalues back to the original eigenvalue problem.
309: Not Collective
311: Input Parameters:
312: st - the spectral transformation context
313: eigr - real part of a computed eigenvalue
314: eigi - imaginary part of a computed eigenvalue
316: Level: developer
317: @*/
318: PetscErrorCode STBackTransform(ST st,PetscInt n,PetscScalar* eigr,PetscScalar* eigi)
319: {
324: if (st->ops->backtr) {
325: (*st->ops->backtr)(st,n,eigr,eigi);
326: }
327: return(0);
328: }