xref: /petsc/src/mat/impls/aij/seq/bas/basfactor.c (revision ccfb0f9f40a0131988d7995ed9679700dae2a75a)
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, missing;
10   PetscInt        reallocs = 0, i, *ai = a->i, *aj = a->j, am = A->rmap->n, *ui;
11   const PetscInt *rip, *riip;
12   PetscInt        j;
13   PetscInt        d;
14   PetscInt        ncols, *cols, *uj;
15   PetscReal       fill = info->fill, levels = info->levels;
16   IS              iperm;
17   spbas_matrix    Pattern_0, Pattern_P;
18 
19   PetscFunctionBegin;
20   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);
21   PetscCall(MatMissingDiagonal(A, &missing, &d));
22   PetscCheck(!missing, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Matrix is missing diagonal entry %" PetscInt_FMT, d);
23   PetscCall(ISIdentity(perm, &perm_identity));
24   PetscCall(ISInvertPermutation(perm, PETSC_DECIDE, &iperm));
25 
26   /* ICC(0) without matrix ordering: simply copies fill pattern */
27   if (!levels && perm_identity) {
28     PetscCall(PetscMalloc1(am + 1, &ui));
29     ui[0] = 0;
30 
31     for (i = 0; i < am; i++) ui[i + 1] = ui[i] + ai[i + 1] - a->diag[i];
32     PetscCall(PetscMalloc1(ui[am] + 1, &uj));
33     cols = uj;
34     for (i = 0; i < am; i++) {
35       aj    = a->j + a->diag[i];
36       ncols = ui[i + 1] - ui[i];
37       for (j = 0; j < ncols; j++) *cols++ = *aj++;
38     }
39   } else { /* case: levels>0 || (levels=0 && !perm_identity) */
40     PetscCall(ISGetIndices(iperm, &riip));
41     PetscCall(ISGetIndices(perm, &rip));
42 
43     /* Create spbas_matrix for pattern */
44     PetscCall(spbas_pattern_only(am, am, ai, aj, &Pattern_0));
45 
46     /* Apply the permutation */
47     PetscCall(spbas_apply_reordering(&Pattern_0, rip, riip));
48 
49     /* Raise the power */
50     PetscCall(spbas_power(Pattern_0, (int)levels + 1, &Pattern_P));
51     PetscCall(spbas_delete(Pattern_0));
52 
53     /* Keep only upper triangle of pattern */
54     PetscCall(spbas_keep_upper(&Pattern_P));
55 
56     /* Convert to Sparse Row Storage  */
57     PetscCall(spbas_matrix_to_crs(Pattern_P, NULL, &ui, &uj));
58     PetscCall(spbas_delete(Pattern_P));
59   } /* end of case: levels>0 || (levels=0 && !perm_identity) */
60 
61   /* put together the new matrix in MATSEQSBAIJ format */
62 
63   b = (Mat_SeqSBAIJ *)fact->data;
64   PetscCall(PetscMalloc1(ui[am], &b->a));
65 
66   b->j    = uj;
67   b->i    = ui;
68   b->diag = NULL;
69   b->ilen = NULL;
70   b->imax = NULL;
71   b->row  = perm;
72   b->col  = perm;
73 
74   PetscCall(PetscObjectReference((PetscObject)perm));
75   PetscCall(PetscObjectReference((PetscObject)perm));
76 
77   b->icol          = iperm;
78   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
79   PetscCall(PetscMalloc1(am, &b->solve_work));
80   b->maxnz = b->nz = ui[am];
81   b->free_a        = PETSC_TRUE;
82   b->free_ij       = PETSC_TRUE;
83 
84   fact->info.factor_mallocs   = reallocs;
85   fact->info.fill_ratio_given = fill;
86   if (ai[am] != 0) {
87     fact->info.fill_ratio_needed = (PetscReal)ui[am] / (PetscReal)ai[am];
88   } else {
89     fact->info.fill_ratio_needed = 0.0;
90   }
91   /*  fact->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_inplace; */
92   PetscFunctionReturn(PETSC_SUCCESS);
93 }
94 
95 static PetscErrorCode MatCholeskyFactorNumeric_SeqAIJ_Bas(Mat B, Mat A, const MatFactorInfo *info)
96 {
97   Mat             C  = B;
98   Mat_SeqSBAIJ   *b  = (Mat_SeqSBAIJ *)C->data;
99   IS              ip = b->row, iip = b->icol;
100   const PetscInt *rip, *riip;
101   PetscInt        mbs = A->rmap->n, *bi = b->i, *bj = b->j;
102   MatScalar      *ba      = b->a;
103   PetscReal       shiftnz = info->shiftamount;
104   PetscReal       droptol = -1;
105   PetscBool       perm_identity;
106   spbas_matrix    Pattern, matrix_L, matrix_LT;
107   PetscReal       mem_reduction;
108 
109   PetscFunctionBegin;
110   /* Reduce memory requirements:   erase values of B-matrix */
111   PetscCall(PetscFree(ba));
112   /*   Compress (maximum) sparseness pattern of B-matrix */
113   PetscCall(spbas_compress_pattern(bi, bj, mbs, mbs, SPBAS_DIAGONAL_OFFSETS, &Pattern, &mem_reduction));
114   PetscCall(PetscFree(bi));
115   PetscCall(PetscFree(bj));
116 
117   PetscCall(PetscInfo(NULL, "    compression rate for spbas_compress_pattern %g \n", (double)mem_reduction));
118 
119   /* Make Cholesky decompositions with larger Manteuffel shifts until no more    negative diagonals are found. */
120   PetscCall(ISGetIndices(ip, &rip));
121   PetscCall(ISGetIndices(iip, &riip));
122 
123   if (info->usedt) droptol = info->dt;
124 
125   for (int ierr = NEGATIVE_DIAGONAL; ierr == NEGATIVE_DIAGONAL;) {
126     PetscBool success;
127 
128     ierr = (int)spbas_incomplete_cholesky(A, rip, riip, Pattern, droptol, shiftnz, &matrix_LT, &success);
129     if (!success) {
130       shiftnz *= 1.5;
131       if (shiftnz < 1e-5) shiftnz = 1e-5;
132       PetscCall(PetscInfo(NULL, "spbas_incomplete_cholesky found a negative diagonal. Trying again with Manteuffel shift=%g\n", (double)shiftnz));
133     }
134   }
135   PetscCall(spbas_delete(Pattern));
136 
137   PetscCall(PetscInfo(NULL, "    memory_usage for  spbas_incomplete_cholesky  %g bytes per row\n", (double)(spbas_memory_requirement(matrix_LT) / (PetscReal)mbs)));
138 
139   PetscCall(ISRestoreIndices(ip, &rip));
140   PetscCall(ISRestoreIndices(iip, &riip));
141 
142   /* Convert spbas_matrix to compressed row storage */
143   PetscCall(spbas_transpose(matrix_LT, &matrix_L));
144   PetscCall(spbas_delete(matrix_LT));
145   PetscCall(spbas_matrix_to_crs(matrix_L, &ba, &bi, &bj));
146   b->i = bi;
147   b->j = bj;
148   b->a = ba;
149   PetscCall(spbas_delete(matrix_L));
150 
151   /* Set the appropriate solution functions */
152   PetscCall(ISIdentity(ip, &perm_identity));
153   if (perm_identity) {
154     B->ops->solve          = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
155     B->ops->solvetranspose = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
156     B->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
157     B->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
158   } else {
159     B->ops->solve          = MatSolve_SeqSBAIJ_1_inplace;
160     B->ops->solvetranspose = MatSolve_SeqSBAIJ_1_inplace;
161     B->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_inplace;
162     B->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_inplace;
163   }
164 
165   C->assembled    = PETSC_TRUE;
166   C->preallocated = PETSC_TRUE;
167 
168   PetscCall(PetscLogFlops(C->rmap->n));
169   PetscFunctionReturn(PETSC_SUCCESS);
170 }
171 
172 static PetscErrorCode MatFactorGetSolverType_seqaij_bas(Mat A, MatSolverType *type)
173 {
174   PetscFunctionBegin;
175   *type = MATSOLVERBAS;
176   PetscFunctionReturn(PETSC_SUCCESS);
177 }
178 
179 PETSC_INTERN PetscErrorCode MatGetFactor_seqaij_bas(Mat A, MatFactorType ftype, Mat *B)
180 {
181   PetscInt n = A->rmap->n;
182 
183   PetscFunctionBegin;
184   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
185   PetscCall(MatSetSizes(*B, n, n, n, n));
186   PetscCheck(ftype == MAT_FACTOR_ICC, PETSC_COMM_SELF, PETSC_ERR_SUP, "Factor type not supported");
187   PetscCall(MatSetType(*B, MATSEQSBAIJ));
188   PetscCall(MatSeqSBAIJSetPreallocation(*B, 1, MAT_SKIP_ALLOCATION, NULL));
189 
190   (*B)->ops->iccfactorsymbolic     = MatICCFactorSymbolic_SeqAIJ_Bas;
191   (*B)->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_Bas;
192   PetscCall(PetscObjectComposeFunction((PetscObject)*B, "MatFactorGetSolverType_C", MatFactorGetSolverType_seqaij_bas));
193   PetscCall(PetscStrallocpy(MATORDERINGND, (char **)&(*B)->preferredordering[MAT_FACTOR_LU]));
194   PetscCall(PetscStrallocpy(MATORDERINGND, (char **)&(*B)->preferredordering[MAT_FACTOR_CHOLESKY]));
195   (*B)->factortype = ftype;
196 
197   PetscCall(PetscFree((*B)->solvertype));
198   PetscCall(PetscStrallocpy(MATSOLVERBAS, &(*B)->solvertype));
199   (*B)->canuseordering = PETSC_TRUE;
200   PetscCall(PetscStrallocpy(MATORDERINGNATURAL, (char **)&(*B)->preferredordering[MAT_FACTOR_ICC]));
201   PetscFunctionReturn(PETSC_SUCCESS);
202 }
203