xref: /petsc/src/mat/impls/aij/seq/bas/basfactor.c (revision d5b43468fb8780a8feea140ccd6fa3e6a50411cc)
1 
2 #include <../src/mat/impls/aij/seq/aij.h>
3 #include <../src/mat/impls/sbaij/seq/sbaij.h>
4 #include <../src/mat/impls/aij/seq/bas/spbas.h>
5 
6 PetscErrorCode MatICCFactorSymbolic_SeqAIJ_Bas(Mat fact, Mat A, IS perm, const MatFactorInfo *info)
7 {
8   Mat_SeqAIJ     *a = (Mat_SeqAIJ *)A->data;
9   Mat_SeqSBAIJ   *b;
10   PetscBool       perm_identity, missing;
11   PetscInt        reallocs = 0, i, *ai = a->i, *aj = a->j, am = A->rmap->n, *ui;
12   const PetscInt *rip, *riip;
13   PetscInt        j;
14   PetscInt        d;
15   PetscInt        ncols, *cols, *uj;
16   PetscReal       fill = info->fill, levels = info->levels;
17   IS              iperm;
18   spbas_matrix    Pattern_0, Pattern_P;
19 
20   PetscFunctionBegin;
21   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);
22   PetscCall(MatMissingDiagonal(A, &missing, &d));
23   PetscCheck(!missing, PETSC_COMM_SELF, PETSC_ERR_ARG_WRONGSTATE, "Matrix is missing diagonal entry %" PetscInt_FMT, d);
24   PetscCall(ISIdentity(perm, &perm_identity));
25   PetscCall(ISInvertPermutation(perm, PETSC_DECIDE, &iperm));
26 
27   /* ICC(0) without matrix ordering: simply copies fill pattern */
28   if (!levels && perm_identity) {
29     PetscCall(PetscMalloc1(am + 1, &ui));
30     ui[0] = 0;
31 
32     for (i = 0; i < am; i++) ui[i + 1] = ui[i] + ai[i + 1] - a->diag[i];
33     PetscCall(PetscMalloc1(ui[am] + 1, &uj));
34     cols = uj;
35     for (i = 0; i < am; i++) {
36       aj    = a->j + a->diag[i];
37       ncols = ui[i + 1] - ui[i];
38       for (j = 0; j < ncols; j++) *cols++ = *aj++;
39     }
40   } else { /* case: levels>0 || (levels=0 && !perm_identity) */
41     PetscCall(ISGetIndices(iperm, &riip));
42     PetscCall(ISGetIndices(perm, &rip));
43 
44     /* Create spbas_matrix for pattern */
45     PetscCall(spbas_pattern_only(am, am, ai, aj, &Pattern_0));
46 
47     /* Apply the permutation */
48     PetscCall(spbas_apply_reordering(&Pattern_0, rip, riip));
49 
50     /* Raise the power */
51     PetscCall(spbas_power(Pattern_0, (int)levels + 1, &Pattern_P));
52     PetscCall(spbas_delete(Pattern_0));
53 
54     /* Keep only upper triangle of pattern */
55     PetscCall(spbas_keep_upper(&Pattern_P));
56 
57     /* Convert to Sparse Row Storage  */
58     PetscCall(spbas_matrix_to_crs(Pattern_P, NULL, &ui, &uj));
59     PetscCall(spbas_delete(Pattern_P));
60   } /* end of case: levels>0 || (levels=0 && !perm_identity) */
61 
62   /* put together the new matrix in MATSEQSBAIJ format */
63 
64   b               = (Mat_SeqSBAIJ *)(fact)->data;
65   b->singlemalloc = PETSC_FALSE;
66 
67   PetscCall(PetscMalloc1(ui[am] + 1, &b->a));
68 
69   b->j    = uj;
70   b->i    = ui;
71   b->diag = NULL;
72   b->ilen = NULL;
73   b->imax = NULL;
74   b->row  = perm;
75   b->col  = perm;
76 
77   PetscCall(PetscObjectReference((PetscObject)perm));
78   PetscCall(PetscObjectReference((PetscObject)perm));
79 
80   b->icol          = iperm;
81   b->pivotinblocks = PETSC_FALSE; /* need to get from MatFactorInfo */
82   PetscCall(PetscMalloc1(am + 1, &b->solve_work));
83   b->maxnz = b->nz = ui[am];
84   b->free_a        = PETSC_TRUE;
85   b->free_ij       = PETSC_TRUE;
86 
87   (fact)->info.factor_mallocs   = reallocs;
88   (fact)->info.fill_ratio_given = fill;
89   if (ai[am] != 0) {
90     (fact)->info.fill_ratio_needed = ((PetscReal)ui[am]) / ((PetscReal)ai[am]);
91   } else {
92     (fact)->info.fill_ratio_needed = 0.0;
93   }
94   /*  (fact)->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_inplace; */
95   PetscFunctionReturn(0);
96 }
97 
98 PetscErrorCode MatCholeskyFactorNumeric_SeqAIJ_Bas(Mat B, Mat A, const MatFactorInfo *info)
99 {
100   Mat             C  = B;
101   Mat_SeqSBAIJ   *b  = (Mat_SeqSBAIJ *)C->data;
102   IS              ip = b->row, iip = b->icol;
103   const PetscInt *rip, *riip;
104   PetscInt        mbs = A->rmap->n, *bi = b->i, *bj = b->j;
105   MatScalar      *ba      = b->a;
106   PetscReal       shiftnz = info->shiftamount;
107   PetscReal       droptol = -1;
108   PetscBool       perm_identity;
109   spbas_matrix    Pattern, matrix_L, matrix_LT;
110   PetscReal       mem_reduction;
111 
112   PetscFunctionBegin;
113   /* Reduce memory requirements:   erase values of B-matrix */
114   PetscCall(PetscFree(ba));
115   /*   Compress (maximum) sparseness pattern of B-matrix */
116   PetscCall(spbas_compress_pattern(bi, bj, mbs, mbs, SPBAS_DIAGONAL_OFFSETS, &Pattern, &mem_reduction));
117   PetscCall(PetscFree(bi));
118   PetscCall(PetscFree(bj));
119 
120   PetscCall(PetscInfo(NULL, "    compression rate for spbas_compress_pattern %g \n", (double)mem_reduction));
121 
122   /* Make Cholesky decompositions with larger Manteuffel shifts until no more    negative diagonals are found. */
123   PetscCall(ISGetIndices(ip, &rip));
124   PetscCall(ISGetIndices(iip, &riip));
125 
126   if (info->usedt) droptol = info->dt;
127 
128   for (PetscErrorCode ierr = NEGATIVE_DIAGONAL; ierr == NEGATIVE_DIAGONAL;) {
129     PetscBool success;
130 
131     ierr = spbas_incomplete_cholesky(A, rip, riip, Pattern, droptol, shiftnz, &matrix_LT, &success);
132     if (!success) {
133       shiftnz *= 1.5;
134       if (shiftnz < 1e-5) shiftnz = 1e-5;
135       PetscCall(PetscInfo(NULL, "spbas_incomplete_cholesky found a negative diagonal. Trying again with Manteuffel shift=%g\n", (double)shiftnz));
136     }
137   }
138   PetscCall(spbas_delete(Pattern));
139 
140   PetscCall(PetscInfo(NULL, "    memory_usage for  spbas_incomplete_cholesky  %g bytes per row\n", (double)(PetscReal)(spbas_memory_requirement(matrix_LT) / (PetscReal)mbs)));
141 
142   PetscCall(ISRestoreIndices(ip, &rip));
143   PetscCall(ISRestoreIndices(iip, &riip));
144 
145   /* Convert spbas_matrix to compressed row storage */
146   PetscCall(spbas_transpose(matrix_LT, &matrix_L));
147   PetscCall(spbas_delete(matrix_LT));
148   PetscCall(spbas_matrix_to_crs(matrix_L, &ba, &bi, &bj));
149   b->i = bi;
150   b->j = bj;
151   b->a = ba;
152   PetscCall(spbas_delete(matrix_L));
153 
154   /* Set the appropriate solution functions */
155   PetscCall(ISIdentity(ip, &perm_identity));
156   if (perm_identity) {
157     (B)->ops->solve          = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
158     (B)->ops->solvetranspose = MatSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
159     (B)->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
160     (B)->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_NaturalOrdering_inplace;
161   } else {
162     (B)->ops->solve          = MatSolve_SeqSBAIJ_1_inplace;
163     (B)->ops->solvetranspose = MatSolve_SeqSBAIJ_1_inplace;
164     (B)->ops->forwardsolve   = MatForwardSolve_SeqSBAIJ_1_inplace;
165     (B)->ops->backwardsolve  = MatBackwardSolve_SeqSBAIJ_1_inplace;
166   }
167 
168   C->assembled    = PETSC_TRUE;
169   C->preallocated = PETSC_TRUE;
170 
171   PetscCall(PetscLogFlops(C->rmap->n));
172   PetscFunctionReturn(0);
173 }
174 
175 PetscErrorCode MatFactorGetSolverType_seqaij_bas(Mat A, MatSolverType *type)
176 {
177   PetscFunctionBegin;
178   *type = MATSOLVERBAS;
179   PetscFunctionReturn(0);
180 }
181 
182 PETSC_INTERN PetscErrorCode MatGetFactor_seqaij_bas(Mat A, MatFactorType ftype, Mat *B)
183 {
184   PetscInt n = A->rmap->n;
185 
186   PetscFunctionBegin;
187   PetscCall(MatCreate(PetscObjectComm((PetscObject)A), B));
188   PetscCall(MatSetSizes(*B, n, n, n, n));
189   if (ftype == MAT_FACTOR_ICC) {
190     PetscCall(MatSetType(*B, MATSEQSBAIJ));
191     PetscCall(MatSeqSBAIJSetPreallocation(*B, 1, MAT_SKIP_ALLOCATION, NULL));
192 
193     (*B)->ops->iccfactorsymbolic     = MatICCFactorSymbolic_SeqAIJ_Bas;
194     (*B)->ops->choleskyfactornumeric = MatCholeskyFactorNumeric_SeqAIJ_Bas;
195     PetscCall(PetscObjectComposeFunction((PetscObject)*B, "MatFactorGetSolverType_C", MatFactorGetSolverType_seqaij_bas));
196     PetscCall(PetscStrallocpy(MATORDERINGND, (char **)&(*B)->preferredordering[MAT_FACTOR_LU]));
197     PetscCall(PetscStrallocpy(MATORDERINGND, (char **)&(*B)->preferredordering[MAT_FACTOR_CHOLESKY]));
198   } else SETERRQ(PETSC_COMM_SELF, PETSC_ERR_SUP, "Factor type not supported");
199   (*B)->factortype = ftype;
200 
201   PetscCall(PetscFree((*B)->solvertype));
202   PetscCall(PetscStrallocpy(MATSOLVERBAS, &(*B)->solvertype));
203   (*B)->canuseordering = PETSC_TRUE;
204   PetscCall(PetscStrallocpy(MATORDERINGNATURAL, (char **)&(*B)->preferredordering[MAT_FACTOR_ICC]));
205   PetscFunctionReturn(0);
206 }
207