Actual source code: mfnsetup.c
slepc-main 2024-11-22
1: /*
2: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
3: SLEPc - Scalable Library for Eigenvalue Problem Computations
4: Copyright (c) 2002-, Universitat Politecnica de Valencia, Spain
6: This file is part of SLEPc.
7: SLEPc is distributed under a 2-clause BSD license (see LICENSE).
8: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
9: */
10: /*
11: MFN routines related to problem setup
12: */
14: #include <slepc/private/mfnimpl.h>
16: /*@
17: MFNSetUp - Sets up all the internal data structures necessary for the
18: execution of the matrix function solver.
20: Collective
22: Input Parameter:
23: . mfn - matrix function context
25: Notes:
26: This function need not be called explicitly in most cases, since MFNSolve()
27: calls it. It can be useful when one wants to measure the set-up time
28: separately from the solve time.
30: Level: developer
32: .seealso: MFNCreate(), MFNSolve(), MFNDestroy()
33: @*/
34: PetscErrorCode MFNSetUp(MFN mfn)
35: {
36: PetscInt N;
38: PetscFunctionBegin;
41: /* reset the convergence flag from the previous solves */
42: mfn->reason = MFN_CONVERGED_ITERATING;
44: if (mfn->setupcalled) PetscFunctionReturn(PETSC_SUCCESS);
45: PetscCall(PetscLogEventBegin(MFN_SetUp,mfn,0,0,0));
47: /* Set default solver type (MFNSetFromOptions was not called) */
48: if (!((PetscObject)mfn)->type_name) PetscCall(MFNSetType(mfn,MFNKRYLOV));
49: if (!mfn->fn) PetscCall(MFNGetFN(mfn,&mfn->fn));
50: if (!((PetscObject)mfn->fn)->type_name) PetscCall(FNSetFromOptions(mfn->fn));
52: /* Check problem dimensions */
53: PetscCheck(mfn->A,PetscObjectComm((PetscObject)mfn),PETSC_ERR_ARG_WRONGSTATE,"MFNSetOperator must be called first");
54: PetscCall(MatGetSize(mfn->A,&N,NULL));
55: if (mfn->ncv > N) mfn->ncv = N;
57: /* call specific solver setup */
58: PetscUseTypeMethod(mfn,setup);
60: /* set tolerance if not yet set */
61: if (mfn->tol==(PetscReal)PETSC_DETERMINE) mfn->tol = SLEPC_DEFAULT_TOL;
63: PetscCall(PetscLogEventEnd(MFN_SetUp,mfn,0,0,0));
64: mfn->setupcalled = 1;
65: PetscFunctionReturn(PETSC_SUCCESS);
66: }
68: /*@
69: MFNSetOperator - Sets the matrix for which the matrix function is to be computed.
71: Collective
73: Input Parameters:
74: + mfn - the matrix function context
75: - A - the problem matrix
77: Notes:
78: It must be called before MFNSetUp(). If it is called again after MFNSetUp() then
79: the MFN object is reset.
81: Level: beginner
83: .seealso: MFNSolve(), MFNSetUp(), MFNReset()
84: @*/
85: PetscErrorCode MFNSetOperator(MFN mfn,Mat A)
86: {
87: PetscInt m,n;
89: PetscFunctionBegin;
92: PetscCheckSameComm(mfn,1,A,2);
94: PetscCall(MatGetSize(A,&m,&n));
95: PetscCheck(m==n,PetscObjectComm((PetscObject)mfn),PETSC_ERR_ARG_WRONG,"A is a non-square matrix");
96: PetscCall(PetscObjectReference((PetscObject)A));
97: if (mfn->setupcalled) PetscCall(MFNReset(mfn));
98: else PetscCall(MatDestroy(&mfn->A));
99: mfn->A = A;
100: mfn->setupcalled = 0;
101: PetscFunctionReturn(PETSC_SUCCESS);
102: }
104: /*@
105: MFNGetOperator - Gets the matrix associated with the MFN object.
107: Not Collective
109: Input Parameter:
110: . mfn - the MFN context
112: Output Parameters:
113: . A - the matrix for which the matrix function is to be computed
115: Level: intermediate
117: .seealso: MFNSolve(), MFNSetOperator()
118: @*/
119: PetscErrorCode MFNGetOperator(MFN mfn,Mat *A)
120: {
121: PetscFunctionBegin;
123: PetscAssertPointer(A,2);
124: *A = mfn->A;
125: PetscFunctionReturn(PETSC_SUCCESS);
126: }
128: /*@
129: MFNAllocateSolution - Allocate memory storage for common variables such
130: as the basis vectors.
132: Collective
134: Input Parameters:
135: + mfn - matrix function context
136: - extra - number of additional positions, used for methods that require a
137: working basis slightly larger than ncv
139: Developer Notes:
140: This is SLEPC_EXTERN because it may be required by user plugin MFN
141: implementations.
143: Level: developer
145: .seealso: MFNSetUp()
146: @*/
147: PetscErrorCode MFNAllocateSolution(MFN mfn,PetscInt extra)
148: {
149: PetscInt oldsize,requested;
150: Vec t;
152: PetscFunctionBegin;
153: requested = mfn->ncv + extra;
155: /* oldsize is zero if this is the first time setup is called */
156: PetscCall(BVGetSizes(mfn->V,NULL,NULL,&oldsize));
158: /* allocate basis vectors */
159: if (!mfn->V) PetscCall(MFNGetBV(mfn,&mfn->V));
160: if (!oldsize) {
161: if (!((PetscObject)mfn->V)->type_name) PetscCall(BVSetType(mfn->V,BVMAT));
162: PetscCall(MatCreateVecsEmpty(mfn->A,&t,NULL));
163: PetscCall(BVSetSizesFromVec(mfn->V,t,requested));
164: PetscCall(VecDestroy(&t));
165: } else PetscCall(BVResize(mfn->V,requested,PETSC_FALSE));
166: PetscFunctionReturn(PETSC_SUCCESS);
167: }