Line data Source code
1 : /*
2 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3 : SLEPc - Scalable Library for Eigenvalue Problem Computations
4 : Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain
5 :
6 : This file is part of SLEPc.
7 : SLEPc is distributed under a 2-clause BSD license (see LICENSE).
8 : - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
9 : */
10 : /*
11 : Implements the shift-and-invert technique for eigenvalue problems
12 : */
13 :
14 : #include <slepc/private/stimpl.h>
15 :
16 131172 : static PetscErrorCode STBackTransform_Sinvert(ST st,PetscInt n,PetscScalar *eigr,PetscScalar *eigi)
17 : {
18 131172 : PetscInt j;
19 : #if !defined(PETSC_USE_COMPLEX)
20 131172 : PetscScalar t;
21 : #endif
22 :
23 131172 : PetscFunctionBegin;
24 : #if !defined(PETSC_USE_COMPLEX)
25 401951 : for (j=0;j<n;j++) {
26 270779 : if (eigi[j] == 0) eigr[j] = 1.0 / eigr[j] + st->sigma;
27 : else {
28 51933 : t = eigr[j] * eigr[j] + eigi[j] * eigi[j];
29 51933 : eigr[j] = eigr[j] / t + st->sigma;
30 51933 : eigi[j] = - eigi[j] / t;
31 : }
32 : }
33 : #else
34 : for (j=0;j<n;j++) {
35 : eigr[j] = 1.0 / eigr[j] + st->sigma;
36 : }
37 : #endif
38 131172 : PetscFunctionReturn(PETSC_SUCCESS);
39 : }
40 :
41 202 : static PetscErrorCode STPostSolve_Sinvert(ST st)
42 : {
43 202 : PetscFunctionBegin;
44 202 : if (st->matmode == ST_MATMODE_INPLACE) {
45 2 : if (st->nmat>1) PetscCall(MatAXPY(st->A[0],st->sigma,st->A[1],st->str));
46 1 : else PetscCall(MatShift(st->A[0],st->sigma));
47 2 : st->Astate[0] = ((PetscObject)st->A[0])->state;
48 2 : st->state = ST_STATE_INITIAL;
49 2 : st->opready = PETSC_FALSE;
50 : }
51 202 : PetscFunctionReturn(PETSC_SUCCESS);
52 : }
53 :
54 : /*
55 : Operator (sinvert):
56 : Op P M
57 : if nmat=1: (A-sI)^-1 A-sI NULL
58 : if nmat=2: (A-sB)^-1 B A-sB B
59 : */
60 142 : static PetscErrorCode STComputeOperator_Sinvert(ST st)
61 : {
62 142 : PetscFunctionBegin;
63 : /* if the user did not set the shift, use the target value */
64 142 : if (!st->sigma_set) st->sigma = st->defsigma;
65 142 : PetscCall(PetscObjectReference((PetscObject)st->A[1]));
66 142 : PetscCall(MatDestroy(&st->T[0]));
67 142 : st->T[0] = st->A[1];
68 142 : PetscCall(STMatMAXPY_Private(st,-st->sigma,0.0,0,NULL,PetscNot(st->state==ST_STATE_UPDATED),PETSC_FALSE,&st->T[1]));
69 142 : PetscCall(PetscObjectReference((PetscObject)st->T[1]));
70 142 : PetscCall(MatDestroy(&st->P));
71 142 : st->P = st->T[1];
72 142 : st->M = (st->nmat>1)? st->T[0]: NULL;
73 142 : if (st->Psplit) { /* build custom preconditioner from the split matrices */
74 7 : PetscCall(STMatMAXPY_Private(st,-st->sigma,0.0,0,NULL,PETSC_TRUE,PETSC_TRUE,&st->Pmat));
75 : }
76 142 : PetscFunctionReturn(PETSC_SUCCESS);
77 : }
78 :
79 251 : static PetscErrorCode STSetUp_Sinvert(ST st)
80 : {
81 251 : PetscInt k,nc,nmat=st->nmat;
82 251 : PetscScalar *coeffs=NULL;
83 :
84 251 : PetscFunctionBegin;
85 251 : if (nmat>1) PetscCall(STSetWorkVecs(st,1));
86 : /* if the user did not set the shift, use the target value */
87 251 : if (!st->sigma_set) st->sigma = st->defsigma;
88 251 : if (nmat>2) { /* set-up matrices for polynomial eigenproblems */
89 105 : if (st->transform) {
90 22 : nc = (nmat*(nmat+1))/2;
91 22 : PetscCall(PetscMalloc1(nc,&coeffs));
92 : /* Compute coeffs */
93 22 : PetscCall(STCoeffs_Monomial(st,coeffs));
94 : /* T[0] = A_n */
95 22 : k = nmat-1;
96 22 : PetscCall(PetscObjectReference((PetscObject)st->A[k]));
97 22 : PetscCall(MatDestroy(&st->T[0]));
98 22 : st->T[0] = st->A[k];
99 69 : for (k=1;k<nmat;k++) PetscCall(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),PETSC_FALSE,&st->T[k]));
100 22 : PetscCall(PetscFree(coeffs));
101 22 : PetscCall(PetscObjectReference((PetscObject)st->T[nmat-1]));
102 22 : PetscCall(MatDestroy(&st->P));
103 22 : st->P = st->T[nmat-1];
104 22 : if (st->Psplit) { /* build custom preconditioner from the split matrices */
105 2 : PetscCall(STMatMAXPY_Private(st,st->sigma,0.0,0,coeffs?coeffs+((nmat-1)*nmat)/2:NULL,PETSC_TRUE,PETSC_TRUE,&st->Pmat));
106 : }
107 22 : PetscCall(ST_KSPSetOperators(st,st->P,st->Pmat?st->Pmat:st->P));
108 : } else {
109 465 : for (k=0;k<nmat;k++) {
110 382 : PetscCall(PetscObjectReference((PetscObject)st->A[k]));
111 382 : PetscCall(MatDestroy(&st->T[k]));
112 382 : st->T[k] = st->A[k];
113 : }
114 : }
115 : }
116 251 : if (st->P) PetscCall(KSPSetUp(st->ksp));
117 251 : PetscFunctionReturn(PETSC_SUCCESS);
118 : }
119 :
120 409 : static PetscErrorCode STSetShift_Sinvert(ST st,PetscScalar newshift)
121 : {
122 409 : PetscInt nmat=PetscMax(st->nmat,2),k,nc;
123 409 : PetscScalar *coeffs=NULL;
124 :
125 409 : PetscFunctionBegin;
126 409 : if (st->transform) {
127 377 : if (st->matmode == ST_MATMODE_COPY && nmat>2) {
128 2 : nc = (nmat*(nmat+1))/2;
129 2 : PetscCall(PetscMalloc1(nc,&coeffs));
130 : /* Compute coeffs */
131 2 : PetscCall(STCoeffs_Monomial(st,coeffs));
132 : }
133 760 : for (k=1;k<nmat;k++) PetscCall(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,PETSC_FALSE,&st->T[k]));
134 377 : if (st->matmode == ST_MATMODE_COPY && nmat>2) PetscCall(PetscFree(coeffs));
135 377 : if (st->P!=st->T[nmat-1]) {
136 12 : PetscCall(PetscObjectReference((PetscObject)st->T[nmat-1]));
137 12 : PetscCall(MatDestroy(&st->P));
138 12 : st->P = st->T[nmat-1];
139 : }
140 377 : if (st->Psplit) { /* build custom preconditioner from the split matrices */
141 35 : PetscCall(STMatMAXPY_Private(st,nmat>2?newshift:-newshift,nmat>2?st->sigma:-st->sigma,0,coeffs?coeffs+((nmat-1)*nmat)/2:NULL,PETSC_FALSE,PETSC_TRUE,&st->Pmat));
142 : }
143 : }
144 409 : if (st->P) {
145 407 : PetscCall(ST_KSPSetOperators(st,st->P,st->Pmat?st->Pmat:st->P));
146 407 : PetscCall(KSPSetUp(st->ksp));
147 : }
148 409 : PetscFunctionReturn(PETSC_SUCCESS);
149 : }
150 :
151 236 : SLEPC_EXTERN PetscErrorCode STCreate_Sinvert(ST st)
152 : {
153 236 : PetscFunctionBegin;
154 236 : st->usesksp = PETSC_TRUE;
155 :
156 236 : st->ops->apply = STApply_Generic;
157 236 : st->ops->applytrans = STApplyTranspose_Generic;
158 236 : st->ops->applyhermtrans = STApplyHermitianTranspose_Generic;
159 236 : st->ops->backtransform = STBackTransform_Sinvert;
160 236 : st->ops->setshift = STSetShift_Sinvert;
161 236 : st->ops->getbilinearform = STGetBilinearForm_Default;
162 236 : st->ops->setup = STSetUp_Sinvert;
163 236 : st->ops->computeoperator = STComputeOperator_Sinvert;
164 236 : st->ops->postsolve = STPostSolve_Sinvert;
165 236 : st->ops->checknullspace = STCheckNullSpace_Default;
166 236 : st->ops->setdefaultksp = STSetDefaultKSP_Default;
167 236 : PetscFunctionReturn(PETSC_SUCCESS);
168 : }
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