Actual source code: sinvert.c
slepc-3.7.2 2016-07-19
1: /*
2: Implements the shift-and-invert technique for eigenvalue problems.
4: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
5: SLEPc - Scalable Library for Eigenvalue Problem Computations
6: Copyright (c) 2002-2016, Universitat Politecnica de Valencia, Spain
8: This file is part of SLEPc.
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 <slepc/private/stimpl.h>
28: PetscErrorCode STApply_Sinvert(ST st,Vec x,Vec y)
29: {
33: if (st->nmat>1) {
34: /* generalized eigenproblem: y = (A - sB)^-1 B x */
35: MatMult(st->T[0],x,st->w);
36: STMatSolve(st,st->w,y);
37: } else {
38: /* standard eigenproblem: y = (A - sI)^-1 x */
39: STMatSolve(st,x,y);
40: }
41: return(0);
42: }
46: PetscErrorCode STApplyTranspose_Sinvert(ST st,Vec x,Vec y)
47: {
51: if (st->nmat>1) {
52: /* generalized eigenproblem: y = B^T (A - sB)^-T x */
53: STMatSolveTranspose(st,x,st->w);
54: MatMultTranspose(st->T[0],st->w,y);
55: } else {
56: /* standard eigenproblem: y = (A - sI)^-T x */
57: STMatSolveTranspose(st,x,y);
58: }
59: return(0);
60: }
64: PetscErrorCode STBackTransform_Sinvert(ST st,PetscInt n,PetscScalar *eigr,PetscScalar *eigi)
65: {
66: PetscInt j;
67: #if !defined(PETSC_USE_COMPLEX)
68: PetscScalar t;
69: #endif
72: #if !defined(PETSC_USE_COMPLEX)
73: for (j=0;j<n;j++) {
74: if (eigi[j] == 0) eigr[j] = 1.0 / eigr[j] + st->sigma;
75: else {
76: t = eigr[j] * eigr[j] + eigi[j] * eigi[j];
77: eigr[j] = eigr[j] / t + st->sigma;
78: eigi[j] = - eigi[j] / t;
79: }
80: }
81: #else
82: for (j=0;j<n;j++) {
83: eigr[j] = 1.0 / eigr[j] + st->sigma;
84: }
85: #endif
86: return(0);
87: }
91: PetscErrorCode STPostSolve_Sinvert(ST st)
92: {
96: if (st->shift_matrix == ST_MATMODE_INPLACE) {
97: if (st->nmat>1) {
98: MatAXPY(st->A[0],st->sigma,st->A[1],st->str);
99: } else {
100: MatShift(st->A[0],st->sigma);
101: }
102: st->Astate[0] = ((PetscObject)st->A[0])->state;
103: st->state = ST_STATE_INITIAL;
104: }
105: return(0);
106: }
110: PetscErrorCode STSetUp_Sinvert(ST st)
111: {
113: PetscInt k,nc,nmat=PetscMax(st->nmat,2);
114: PetscScalar *coeffs=NULL;
117: if (st->nmat>1) {
118: ST_AllocateWorkVec(st);
119: }
120: /* if the user did not set the shift, use the target value */
121: if (!st->sigma_set) st->sigma = st->defsigma;
122: if (st->transform) {
123: if (nmat>2) {
124: nc = (nmat*(nmat+1))/2;
125: PetscMalloc(nc*sizeof(PetscScalar),&coeffs);
126: /* Compute coeffs */
127: STCoeffs_Monomial(st,coeffs);
128: }
129: /* T[0] = A_n */
130: k = nmat-1;
131: PetscObjectReference((PetscObject)st->A[k]);
132: MatDestroy(&st->T[0]);
133: st->T[0] = st->A[k];
134: for (k=1;k<nmat;k++) {
135: STMatMAXPY_Private(st,nmat>2?st->sigma:-st->sigma,0.0,nmat-k-1,coeffs?coeffs+(k*(k+1))/2:NULL,PetscNot(st->state==ST_STATE_UPDATED),&st->T[k]);
136: }
137: if (nmat>2) { PetscFree(coeffs); }
138: PetscObjectReference((PetscObject)st->T[nmat-1]);
139: MatDestroy(&st->P);
140: st->P = st->T[nmat-1];
141: } else {
142: for (k=0;k<nmat;k++) {
143: PetscObjectReference((PetscObject)st->A[k]);
144: MatDestroy(&st->T[k]);
145: st->T[k] = st->A[k];
146: }
147: }
148: if (st->P) {
149: if (!st->ksp) { STGetKSP(st,&st->ksp); }
150: STCheckFactorPackage(st);
151: KSPSetOperators(st->ksp,st->P,st->P);
152: KSPSetErrorIfNotConverged(st->ksp,PETSC_TRUE);
153: KSPSetUp(st->ksp);
154: }
155: return(0);
156: }
160: PetscErrorCode STSetShift_Sinvert(ST st,PetscScalar newshift)
161: {
163: PetscInt nmat=PetscMax(st->nmat,2),k,nc;
164: PetscScalar *coeffs=NULL;
167: if (st->transform) {
168: if (st->shift_matrix == ST_MATMODE_COPY && nmat>2) {
169: nc = (nmat*(nmat+1))/2;
170: PetscMalloc(nc*sizeof(PetscScalar),&coeffs);
171: /* Compute coeffs */
172: STCoeffs_Monomial(st,coeffs);
173: }
174: for (k=1;k<nmat;k++) {
175: STMatMAXPY_Private(st,nmat>2?newshift:-newshift,nmat>2?st->sigma:-st->sigma,nmat-k-1,coeffs?coeffs+(k*(k+1))/2:NULL,PETSC_FALSE,&st->T[k]);
176: }
177: if (st->shift_matrix == ST_MATMODE_COPY && nmat>2) {
178: PetscFree(coeffs);
179: }
180: if (st->P!=st->T[nmat-1]) {
181: MatDestroy(&st->P);
182: st->P = st->T[nmat-1];
183: PetscObjectReference((PetscObject)st->P);
184: }
185: }
186: if (st->P) {
187: if (!st->ksp) { STGetKSP(st,&st->ksp); }
188: KSPSetOperators(st->ksp,st->P,st->P);
189: KSPSetUp(st->ksp);
190: }
191: return(0);
192: }
196: PetscErrorCode STSetFromOptions_Sinvert(PetscOptionItems *PetscOptionsObject,ST st)
197: {
199: PC pc;
200: PCType pctype;
201: KSPType ksptype;
204: if (!st->ksp) { STGetKSP(st,&st->ksp); }
205: KSPGetPC(st->ksp,&pc);
206: KSPGetType(st->ksp,&ksptype);
207: PCGetType(pc,&pctype);
208: if (!pctype && !ksptype) {
209: if (st->shift_matrix == ST_MATMODE_SHELL) {
210: /* in shell mode use GMRES with Jacobi as the default */
211: KSPSetType(st->ksp,KSPGMRES);
212: PCSetType(pc,PCJACOBI);
213: } else {
214: /* use direct solver as default */
215: KSPSetType(st->ksp,KSPPREONLY);
216: PCSetType(pc,PCLU);
217: }
218: }
219: return(0);
220: }
224: PETSC_EXTERN PetscErrorCode STCreate_Sinvert(ST st)
225: {
227: st->ops->apply = STApply_Sinvert;
228: st->ops->getbilinearform = STGetBilinearForm_Default;
229: st->ops->applytrans = STApplyTranspose_Sinvert;
230: st->ops->postsolve = STPostSolve_Sinvert;
231: st->ops->backtransform = STBackTransform_Sinvert;
232: st->ops->setup = STSetUp_Sinvert;
233: st->ops->setshift = STSetShift_Sinvert;
234: st->ops->setfromoptions = STSetFromOptions_Sinvert;
235: st->ops->checknullspace = STCheckNullSpace_Default;
236: return(0);
237: }