xref: /petsc/src/mat/impls/aij/seq/bas/basfactor.c (revision a336c15037c72f93cd561f5a5e11e93175f2efd9)
1 #include <../src/mat/impls/aij/seq/aij.h>
2 #include <../src/mat/impls/sbaij/seq/sbaij.h>
3 #include <../src/mat/impls/aij/seq/bas/spbas.h>
4 
5 static PetscErrorCode MatICCFactorSymbolic_SeqAIJ_Bas(Mat fact, Mat A, IS perm, const MatFactorInfo *info)
6 {
7   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
8   Mat_SeqSBAIJ   *b;
9   PetscBool       perm_identity, diagDense;
10   PetscInt        reallocs = 0, i, *ai = a->i, *aj = a->j, am = A->rmap->n, *ui;
11   const PetscInt *rip, *riip, *adiag;
12   PetscInt        j;
13   PetscInt        ncols, *cols, *uj;
14   PetscReal       fill = info->fill, levels = info->levels;
15   IS              iperm;
16   spbas_matrix    Pattern_0, Pattern_P;
17 
18   PetscFunctionBegin;
19   PetscCheck(A->rmap->n == A->cmap->n, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONG, "Must be square matrix, rows %" PetscInt_FMT " columns %" PetscInt_FMT, A->rmap->n, A->cmap->n);
20   PetscCall(MatGetDiagonalMarkers_SeqAIJ(A, &adiag, &diagDense));
21   PetscCheck(diagDense, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Matrix is missing diagonal entries");
22   PetscCall(ISIdentity(perm, &perm_identity));
23   PetscCall(ISInvertPermutation(perm, PETSC_DECIDE, &iperm));
24 
25   /* ICC(0) without matrix ordering: simply copies fill pattern */
26   if (!levels && perm_identity) {
27     PetscCall(PetscMalloc1(am + 1, &ui));
28     ui[0] = 0;
29 
30     for (i = 0; i < am; i++) ui[i + 1] = ui[i] + ai[i + 1] - adiag[i];
31     PetscCall(PetscMalloc1(ui[am] + 1, &uj));
32     cols = uj;
33     for (i = 0; i < am; i++) {
34       aj    = a->j + adiag[i];
35       ncols = ui[i + 1] - ui[i];
36       for (j = 0; j < ncols; j++) *cols++ = *aj++;
37     }
38   } else { /* case: levels>0 || (levels=0 && !perm_identity) */
39     PetscCall(ISGetIndices(iperm, &riip));
40     PetscCall(ISGetIndices(perm, &rip));
41 
42     /* Create spbas_matrix for pattern */
43     PetscCall(spbas_pattern_only(am, am, ai, aj, &Pattern_0));
44 
45     /* Apply the permutation */
46     PetscCall(spbas_apply_reordering(&Pattern_0, rip, riip));
47 
48     /* Raise the power */
49     PetscCall(spbas_power(Pattern_0, (int)levels + 1, &Pattern_P));
50     PetscCall(spbas_delete(Pattern_0));
51 
52     /* Keep only upper triangle of pattern */
53     PetscCall(spbas_keep_upper(&Pattern_P));
54 
55     /* Convert to Sparse Row Storage  */
56     PetscCall(spbas_matrix_to_crs(Pattern_P, NULL, &ui, &uj));
57     PetscCall(spbas_delete(Pattern_P));
58   } /* end of case: levels>0 || (levels=0 && !perm_identity) */
59 
60   /* put together the new matrix in MATSEQSBAIJ format */
61 
62   b = (Mat_SeqSBAIJ *)fact->data;
63   PetscCall(PetscMalloc1(ui[am], &b->a));
64 
65   b->j    = uj;
66   b->i    = ui;
67   b->diag = NULL;
68   b->ilen = NULL;
69   b->imax = NULL;
70   b->row  = perm;
71   b->col  = perm;
72 
73   PetscCall(PetscObjectReference((PetscObject)perm));
74   PetscCall(PetscObjectReference((PetscObject)perm));
75 
76   b->icol          = iperm;
77   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
78   PetscCall(PetscMalloc1(am, &b->solve_work));
79   b->maxnz = b->nz = ui[am];
80   b->free_a        = PETSC_TRUE;
81   b->free_ij       = PETSC_TRUE;
82 
83   fact->info.factor_mallocs   = reallocs;
84   fact->info.fill_ratio_given = fill;
85   if (ai[am] != 0) {
86     fact->info.fill_ratio_needed = (PetscReal)ui[am] / (PetscReal)ai[am];
87   } else {
88     fact->info.fill_ratio_needed = 0.0;
89   }
90   /*  fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_inplace; */
91   PetscFunctionReturn(PETSC_SUCCESS);
92 }
93 
94 static PetscErrorCode MatCholeskyFactorNumeric_SeqAIJ_Bas(Mat B, Mat A, const MatFactorInfo *info)
95 {
96   Mat             C  = B;
97   Mat_SeqSBAIJ   *b  = (Mat_SeqSBAIJ *)C->data;
98   IS              ip = b->row, iip = b->icol;
99   const PetscInt *rip, *riip;
100   PetscInt        mbs = A->rmap->n, *bi = b->i, *bj = b->j;
101   MatScalar      *ba      = b->a;
102   PetscReal       shiftnz = info->shiftamount;
103   PetscReal       droptol = -1;
104   PetscBool       perm_identity;
105   spbas_matrix    Pattern, matrix_L, matrix_LT;
106   PetscReal       mem_reduction;
107 
108   PetscFunctionBegin;
109   /* Reduce memory requirements:   erase values of B-matrix */
110   PetscCall(PetscFree(ba));
111   /*   Compress (maximum) sparseness pattern of B-matrix */
112   PetscCall(spbas_compress_pattern(bi, bj, mbs, mbs, SPBAS_DIAGONAL_OFFSETS, &Pattern, &mem_reduction));
113   PetscCall(PetscFree(bi));
114   PetscCall(PetscFree(bj));
115 
116   PetscCall(PetscInfo(NULL, "    compression rate for spbas_compress_pattern %g \n", (double)mem_reduction));
117 
118   /* Make Cholesky decompositions with larger Manteuffel shifts until no more    negative diagonals are found. */
119   PetscCall(ISGetIndices(ip, &rip));
120   PetscCall(ISGetIndices(iip, &riip));
121 
122   if (info->usedt) droptol = info->dt;
123 
124   for (int ierr = NEGATIVE_DIAGONAL; ierr == NEGATIVE_DIAGONAL;) {
125     PetscBool success;
126 
127     ierr = (int)spbas_incomplete_cholesky(A, rip, riip, Pattern, droptol, shiftnz, &matrix_LT, &success);
128     if (!success) {
129       shiftnz *= 1.5;
130       if (shiftnz < 1e-5) shiftnz = 1e-5;
131       PetscCall(PetscInfo(NULL, "spbas_incomplete_cholesky found a negative diagonal. Trying again with Manteuffel shift=%g\n", (double)shiftnz));
132     }
133   }
134   PetscCall(spbas_delete(Pattern));
135 
136   PetscCall(PetscInfo(NULL, "    memory_usage for  spbas_incomplete_cholesky  %g bytes per row\n", (double)(spbas_memory_requirement(matrix_LT) / (PetscReal)mbs)));
137 
138   PetscCall(ISRestoreIndices(ip, &rip));
139   PetscCall(ISRestoreIndices(iip, &riip));
140 
141   /* Convert spbas_matrix to compressed row storage */
142   PetscCall(spbas_transpose(matrix_LT, &matrix_L));
143   PetscCall(spbas_delete(matrix_LT));
144   PetscCall(spbas_matrix_to_crs(matrix_L, &ba, &bi, &bj));
145   b->i = bi;
146   b->j = bj;
147   b->a = ba;
148   PetscCall(spbas_delete(matrix_L));
149 
150   /* Set the appropriate solution functions */
151   PetscCall(ISIdentity(ip, &perm_identity));
152   if (perm_identity) {
153     B->ops->solve          = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
154     B->ops->solvetranspose = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
155     B->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
156     B->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
157   } else {
158     B->ops->solve          = MatSolve_SeqSBAIJ_1_inplace;
159     B->ops->solvetranspose = MatSolve_SeqSBAIJ_1_inplace;
160     B->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_inplace;
161     B->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_inplace;
162   }
163 
164   C->assembled    = PETSC_TRUE;
165   C->preallocated = PETSC_TRUE;
166 
167   PetscCall(PetscLogFlops(C->rmap->n));
168   PetscFunctionReturn(PETSC_SUCCESS);
169 }
170 
171 static PetscErrorCode MatFactorGetSolverType_seqaij_bas(Mat A, MatSolverType *type)
172 {
173   PetscFunctionBegin;
174   *type = MATSOLVERBAS;
175   PetscFunctionReturn(PETSC_SUCCESS);
176 }
177 
178 PETSC_INTERN PetscErrorCode MatGetFactor_seqaij_bas(Mat A, MatFactorType ftype, Mat *B)
179 {
180   PetscInt n = A->rmap->n;
181 
182   PetscFunctionBegin;
183   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
184   PetscCall(MatSetSizes(*B, n, n, n, n));
185   PetscCheck(ftype == MAT_FACTOR_ICC, PETSC_COMM_SELF, PETSC_ERR_SUP, "Factor type not supported");
186   PetscCall(MatSetType(*B, MATSEQSBAIJ));
187   PetscCall(MatSeqSBAIJSetPreallocation(*B, 1, MAT_SKIP_ALLOCATION, NULL));
188 
189   (*B)->ops->iccfactorsymbolic     = MatICCFactorSymbolic_SeqAIJ_Bas;
190   (*B)->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_Bas;
191   PetscCall(PetscObjectComposeFunction((PetscObject)*B, "MatFactorGetSolverType_C", MatFactorGetSolverType_seqaij_bas));
192   PetscCall(PetscStrallocpy(MATORDERINGND, (char **)&(*B)->preferredordering[MAT_FACTOR_LU]));
193   PetscCall(PetscStrallocpy(MATORDERINGND, (char **)&(*B)->preferredordering[MAT_FACTOR_CHOLESKY]));
194   (*B)->factortype = ftype;
195 
196   PetscCall(PetscFree((*B)->solvertype));
197   PetscCall(PetscStrallocpy(MATSOLVERBAS, &(*B)->solvertype));
198   (*B)->canuseordering = PETSC_TRUE;
199   PetscCall(PetscStrallocpy(MATORDERINGNATURAL, (char **)&(*B)->preferredordering[MAT_FACTOR_ICC]));
200   PetscFunctionReturn(PETSC_SUCCESS);
201 }
202