xref: /petsc/src/ksp/pc/impls/factor/lu/lu.c (revision 7d0a6c19129e7069c8a40e210b34ed62989173db)
1 
2 /*
3    Defines a direct factorization preconditioner for any Mat implementation
4    Note: this need not be consided a preconditioner since it supplies
5          a direct solver.
6 */
7 
8 #include "../src/ksp/pc/impls/factor/lu/lu.h"  /*I "petscpc.h" I*/
9 
10 EXTERN_C_BEGIN
11 #undef __FUNCT__
12 #define __FUNCT__ "PCFactorReorderForNonzeroDiagonal_LU"
13 PetscErrorCode  PCFactorReorderForNonzeroDiagonal_LU(PC pc,PetscReal z)
14 {
15   PC_LU *lu = (PC_LU*)pc->data;
16 
17   PetscFunctionBegin;
18   lu->nonzerosalongdiagonal = PETSC_TRUE;
19   if (z == PETSC_DECIDE) {
20     lu->nonzerosalongdiagonaltol = 1.e-10;
21   } else {
22     lu->nonzerosalongdiagonaltol = z;
23   }
24   PetscFunctionReturn(0);
25 }
26 EXTERN_C_END
27 
28 EXTERN_C_BEGIN
29 #undef __FUNCT__
30 #define __FUNCT__ "PCFactorSetReuseOrdering_LU"
31 PetscErrorCode  PCFactorSetReuseOrdering_LU(PC pc,PetscBool  flag)
32 {
33   PC_LU *lu = (PC_LU*)pc->data;
34 
35   PetscFunctionBegin;
36   lu->reuseordering = flag;
37   PetscFunctionReturn(0);
38 }
39 EXTERN_C_END
40 
41 EXTERN_C_BEGIN
42 #undef __FUNCT__
43 #define __FUNCT__ "PCFactorSetReuseFill_LU"
44 PetscErrorCode  PCFactorSetReuseFill_LU(PC pc,PetscBool  flag)
45 {
46   PC_LU *lu = (PC_LU*)pc->data;
47 
48   PetscFunctionBegin;
49   lu->reusefill = flag;
50   PetscFunctionReturn(0);
51 }
52 EXTERN_C_END
53 
54 #undef __FUNCT__
55 #define __FUNCT__ "PCSetFromOptions_LU"
56 static PetscErrorCode PCSetFromOptions_LU(PC pc)
57 {
58   PC_LU           *lu = (PC_LU*)pc->data;
59   PetscErrorCode  ierr;
60   PetscBool       flg = PETSC_FALSE;
61   PetscReal       tol;
62 
63   PetscFunctionBegin;
64   ierr = PetscOptionsHead("LU options");CHKERRQ(ierr);
65     ierr = PCSetFromOptions_Factor(pc);CHKERRQ(ierr);
66 
67     ierr = PetscOptionsName("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",&flg);CHKERRQ(ierr);
68     if (flg) {
69       tol = PETSC_DECIDE;
70       ierr = PetscOptionsReal("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",lu->nonzerosalongdiagonaltol,&tol,0);CHKERRQ(ierr);
71       ierr = PCFactorReorderForNonzeroDiagonal(pc,tol);CHKERRQ(ierr);
72     }
73   ierr = PetscOptionsTail();CHKERRQ(ierr);
74   PetscFunctionReturn(0);
75 }
76 
77 #undef __FUNCT__
78 #define __FUNCT__ "PCView_LU"
79 static PetscErrorCode PCView_LU(PC pc,PetscViewer viewer)
80 {
81   PC_LU          *lu = (PC_LU*)pc->data;
82   PetscErrorCode ierr;
83   PetscBool      iascii;
84 
85   PetscFunctionBegin;
86   ierr = PetscTypeCompare((PetscObject)viewer,PETSCVIEWERASCII,&iascii);CHKERRQ(ierr);
87   if (iascii) {
88     if (lu->inplace) {
89       ierr = PetscViewerASCIIPrintf(viewer,"  LU: in-place factorization\n");CHKERRQ(ierr);
90     } else {
91       ierr = PetscViewerASCIIPrintf(viewer,"  LU: out-of-place factorization\n");CHKERRQ(ierr);
92     }
93 
94     if (lu->reusefill)    {ierr = PetscViewerASCIIPrintf(viewer,"       Reusing fill from past factorization\n");CHKERRQ(ierr);}
95     if (lu->reuseordering) {ierr = PetscViewerASCIIPrintf(viewer,"       Reusing reordering from past factorization\n");CHKERRQ(ierr);}
96   }
97   ierr = PCView_Factor(pc,viewer);CHKERRQ(ierr);
98   PetscFunctionReturn(0);
99 }
100 
101 #undef __FUNCT__
102 #define __FUNCT__ "PCSetUp_LU"
103 static PetscErrorCode PCSetUp_LU(PC pc)
104 {
105   PetscErrorCode ierr;
106   PC_LU          *dir = (PC_LU*)pc->data;
107 
108   PetscFunctionBegin;
109   if (dir->reusefill && pc->setupcalled) ((PC_Factor*)dir)->info.fill = dir->actualfill;
110 
111   if (dir->inplace) {
112     if (dir->row && dir->col && dir->row != dir->col) {ierr = ISDestroy(dir->row);CHKERRQ(ierr);}
113     if (dir->col) {ierr = ISDestroy(dir->col);CHKERRQ(ierr);}
114     ierr = MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);CHKERRQ(ierr);
115     if (dir->row) {
116       ierr = PetscLogObjectParent(pc,dir->row);CHKERRQ(ierr);
117       ierr = PetscLogObjectParent(pc,dir->col);CHKERRQ(ierr);
118     }
119     ierr = MatLUFactor(pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
120     ((PC_Factor*)dir)->fact = pc->pmat;
121   } else {
122     MatInfo info;
123     if (!pc->setupcalled) {
124       ierr = MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);CHKERRQ(ierr);
125       if (dir->nonzerosalongdiagonal) {
126         ierr = MatReorderForNonzeroDiagonal(pc->pmat,dir->nonzerosalongdiagonaltol,dir->row,dir->col);CHKERRQ(ierr);
127       }
128       if (dir->row) {
129         ierr = PetscLogObjectParent(pc,dir->row);CHKERRQ(ierr);
130         ierr = PetscLogObjectParent(pc,dir->col);CHKERRQ(ierr);
131       }
132       if (!((PC_Factor*)dir)->fact){
133         ierr = MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_LU,&((PC_Factor*)dir)->fact);CHKERRQ(ierr);
134       }
135       ierr = MatLUFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
136       ierr = MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);CHKERRQ(ierr);
137       dir->actualfill = info.fill_ratio_needed;
138       ierr = PetscLogObjectParent(pc,((PC_Factor*)dir)->fact);CHKERRQ(ierr);
139     } else if (pc->flag != SAME_NONZERO_PATTERN) {
140       if (!dir->reuseordering) {
141         if (dir->row && dir->col && dir->row != dir->col) {ierr = ISDestroy(dir->row);CHKERRQ(ierr);}
142         if (dir->col) {ierr = ISDestroy(dir->col);CHKERRQ(ierr);}
143         ierr = MatGetOrdering(pc->pmat,((PC_Factor*)dir)->ordering,&dir->row,&dir->col);CHKERRQ(ierr);
144         if (dir->nonzerosalongdiagonal) {
145           ierr = MatReorderForNonzeroDiagonal(pc->pmat,dir->nonzerosalongdiagonaltol,dir->row,dir->col);CHKERRQ(ierr);
146         }
147         if (dir->row) {
148           ierr = PetscLogObjectParent(pc,dir->row);CHKERRQ(ierr);
149           ierr = PetscLogObjectParent(pc,dir->col);CHKERRQ(ierr);
150         }
151       }
152       ierr = MatDestroy(((PC_Factor*)dir)->fact);CHKERRQ(ierr);
153       ierr = MatGetFactor(pc->pmat,((PC_Factor*)dir)->solvertype,MAT_FACTOR_LU,&((PC_Factor*)dir)->fact);CHKERRQ(ierr);
154       ierr = MatLUFactorSymbolic(((PC_Factor*)dir)->fact,pc->pmat,dir->row,dir->col,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
155       ierr = MatGetInfo(((PC_Factor*)dir)->fact,MAT_LOCAL,&info);CHKERRQ(ierr);
156       dir->actualfill = info.fill_ratio_needed;
157       ierr = PetscLogObjectParent(pc,((PC_Factor*)dir)->fact);CHKERRQ(ierr);
158     }
159     ierr = MatLUFactorNumeric(((PC_Factor*)dir)->fact,pc->pmat,&((PC_Factor*)dir)->info);CHKERRQ(ierr);
160   }
161   PetscFunctionReturn(0);
162 }
163 
164 #undef __FUNCT__
165 #define __FUNCT__ "PCReset_LU"
166 static PetscErrorCode PCReset_LU(PC pc)
167 {
168   PC_LU          *dir = (PC_LU*)pc->data;
169   PetscErrorCode ierr;
170 
171   PetscFunctionBegin;
172   if (!dir->inplace && ((PC_Factor*)dir)->fact) {ierr = MatDestroy(((PC_Factor*)dir)->fact);CHKERRQ(ierr);}
173   if (dir->row && dir->col && dir->row != dir->col) {ierr = ISDestroy(dir->row);CHKERRQ(ierr);}
174   if (dir->col) {ierr = ISDestroy(dir->col);CHKERRQ(ierr);}
175   PetscFunctionReturn(0);
176 }
177 
178 #undef __FUNCT__
179 #define __FUNCT__ "PCDestroy_LU"
180 static PetscErrorCode PCDestroy_LU(PC pc)
181 {
182   PC_LU          *dir = (PC_LU*)pc->data;
183   PetscErrorCode ierr;
184 
185   PetscFunctionBegin;
186   ierr = PCReset_LU(pc);CHKERRQ(ierr);
187   ierr = PetscFree(((PC_Factor*)dir)->ordering);CHKERRQ(ierr);
188   ierr = PetscFree(((PC_Factor*)dir)->solvertype);CHKERRQ(ierr);
189   ierr = PetscFree(pc->data);CHKERRQ(ierr);
190   PetscFunctionReturn(0);
191 }
192 
193 #undef __FUNCT__
194 #define __FUNCT__ "PCApply_LU"
195 static PetscErrorCode PCApply_LU(PC pc,Vec x,Vec y)
196 {
197   PC_LU          *dir = (PC_LU*)pc->data;
198   PetscErrorCode ierr;
199 
200   PetscFunctionBegin;
201   if (dir->inplace) {ierr = MatSolve(pc->pmat,x,y);CHKERRQ(ierr);}
202   else              {ierr = MatSolve(((PC_Factor*)dir)->fact,x,y);CHKERRQ(ierr);}
203   PetscFunctionReturn(0);
204 }
205 
206 #undef __FUNCT__
207 #define __FUNCT__ "PCApplyTranspose_LU"
208 static PetscErrorCode PCApplyTranspose_LU(PC pc,Vec x,Vec y)
209 {
210   PC_LU          *dir = (PC_LU*)pc->data;
211   PetscErrorCode ierr;
212 
213   PetscFunctionBegin;
214   if (dir->inplace) {ierr = MatSolveTranspose(pc->pmat,x,y);CHKERRQ(ierr);}
215   else              {ierr = MatSolveTranspose(((PC_Factor*)dir)->fact,x,y);CHKERRQ(ierr);}
216   PetscFunctionReturn(0);
217 }
218 
219 /* -----------------------------------------------------------------------------------*/
220 
221 EXTERN_C_BEGIN
222 #undef __FUNCT__
223 #define __FUNCT__ "PCFactorSetUseInPlace_LU"
224 PetscErrorCode  PCFactorSetUseInPlace_LU(PC pc)
225 {
226   PC_LU *dir = (PC_LU*)pc->data;
227 
228   PetscFunctionBegin;
229   dir->inplace = PETSC_TRUE;
230   PetscFunctionReturn(0);
231 }
232 EXTERN_C_END
233 
234 /* ------------------------------------------------------------------------ */
235 
236 /*MC
237    PCLU - Uses a direct solver, based on LU factorization, as a preconditioner
238 
239    Options Database Keys:
240 +  -pc_factor_reuse_ordering - Activate PCFactorSetReuseOrdering()
241 .  -pc_factor_mat_solver_package - Actives PCFactorSetMatSolverPackage() to choose the direct solver, like spooles
242 .  -pc_factor_reuse_fill - Activates PCFactorSetReuseFill()
243 .  -pc_factor_fill <fill> - Sets fill amount
244 .  -pc_factor_in_place - Activates in-place factorization
245 .  -pc_factor_mat_ordering_type <nd,rcm,...> - Sets ordering routine
246 .  -pc_factor_pivot_in_blocks <true,false> - allow pivoting within the small blocks during factorization (may increase
247                                          stability of factorization.
248 .  -pc_factor_shift_type <shifttype> - Sets shift type or PETSC_DECIDE for the default; use '-help' for a list of available types
249 .  -pc_factor_shift_amount <shiftamount> - Sets shift amount or PETSC_DECIDE for the default
250 -   -pc_factor_nonzeros_along_diagonal - permutes the rows and columns to try to put nonzero value along the
251         diagonal.
252 
253    Notes: Not all options work for all matrix formats
254           Run with -help to see additional options for particular matrix formats or factorization
255           algorithms
256 
257    Level: beginner
258 
259    Concepts: LU factorization, direct solver
260 
261    Notes: Usually this will compute an "exact" solution in one iteration and does
262           not need a Krylov method (i.e. you can use -ksp_type preonly, or
263           KSPSetType(ksp,KSPPREONLY) for the Krylov method
264 
265 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC,
266            PCILU, PCCHOLESKY, PCICC, PCFactorSetReuseOrdering(), PCFactorSetReuseFill(), PCFactorGetMatrix(),
267            PCFactorSetFill(), PCFactorSetUseInPlace(), PCFactorSetMatOrderingType(), PCFactorSetColumnPivot(),
268            PCFactorSetPivotingInBlocks(),PCFactorSetShiftType(),PCFactorSetShiftAmount()
269            PCFactorReorderForNonzeroDiagonal()
270 M*/
271 
272 EXTERN_C_BEGIN
273 #undef __FUNCT__
274 #define __FUNCT__ "PCCreate_LU"
275 PetscErrorCode  PCCreate_LU(PC pc)
276 {
277   PetscErrorCode ierr;
278   PetscMPIInt    size;
279   PC_LU          *dir;
280 
281   PetscFunctionBegin;
282   ierr = PetscNewLog(pc,PC_LU,&dir);CHKERRQ(ierr);
283 
284   ierr = MatFactorInfoInitialize(&((PC_Factor*)dir)->info);CHKERRQ(ierr);
285   ((PC_Factor*)dir)->fact       = PETSC_NULL;
286   ((PC_Factor*)dir)->factortype = MAT_FACTOR_LU;
287   dir->inplace                  = PETSC_FALSE;
288   dir->nonzerosalongdiagonal    = PETSC_FALSE;
289 
290   ((PC_Factor*)dir)->info.fill           = 5.0;
291   ((PC_Factor*)dir)->info.dtcol          = 1.e-6; /* default to pivoting; this is only thing PETSc LU supports */
292   ((PC_Factor*)dir)->info.shifttype      = (PetscReal) MAT_SHIFT_NONE;
293   ((PC_Factor*)dir)->info.shiftamount    = 0.0;
294   ((PC_Factor*)dir)->info.zeropivot      = 1.e-12;
295   ((PC_Factor*)dir)->info.pivotinblocks  = 1.0;
296   dir->col                 = 0;
297   dir->row                 = 0;
298 
299   ierr = PetscStrallocpy(MATSOLVERPETSC,&((PC_Factor*)dir)->solvertype);CHKERRQ(ierr); /* default SolverPackage */
300   ierr = MPI_Comm_size(((PetscObject)pc)->comm,&size);CHKERRQ(ierr);
301   if (size == 1) {
302     ierr = PetscStrallocpy(MATORDERINGND,&((PC_Factor*)dir)->ordering);CHKERRQ(ierr);
303   } else {
304     ierr = PetscStrallocpy(MATORDERINGNATURAL,&((PC_Factor*)dir)->ordering);CHKERRQ(ierr);
305   }
306   dir->reusefill        = PETSC_FALSE;
307   dir->reuseordering    = PETSC_FALSE;
308   pc->data              = (void*)dir;
309 
310   pc->ops->reset             = PCReset_LU;
311   pc->ops->destroy           = PCDestroy_LU;
312   pc->ops->apply             = PCApply_LU;
313   pc->ops->applytranspose    = PCApplyTranspose_LU;
314   pc->ops->setup             = PCSetUp_LU;
315   pc->ops->setfromoptions    = PCSetFromOptions_LU;
316   pc->ops->view              = PCView_LU;
317   pc->ops->applyrichardson   = 0;
318   pc->ops->getfactoredmatrix = PCFactorGetMatrix_Factor;
319 
320   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetUpMatSolverPackage_C","PCFactorSetUpMatSolverPackage_Factor",
321                     PCFactorSetUpMatSolverPackage_Factor);CHKERRQ(ierr);
322   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorGetMatSolverPackage_C","PCFactorGetMatSolverPackage_Factor",
323                     PCFactorGetMatSolverPackage_Factor);CHKERRQ(ierr);
324   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetMatSolverPackage_C","PCFactorSetMatSolverPackage_Factor",
325                     PCFactorSetMatSolverPackage_Factor);CHKERRQ(ierr);
326   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetZeroPivot_C","PCFactorSetZeroPivot_Factor",
327                     PCFactorSetZeroPivot_Factor);CHKERRQ(ierr);
328   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftType_C","PCFactorSetShiftType_Factor",
329                     PCFactorSetShiftType_Factor);CHKERRQ(ierr);
330   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftAmount_C","PCFactorSetShiftAmount_Factor",
331                     PCFactorSetShiftAmount_Factor);CHKERRQ(ierr);
332   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetFill_C","PCFactorSetFill_Factor",
333                     PCFactorSetFill_Factor);CHKERRQ(ierr);
334   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetUseInPlace_C","PCFactorSetUseInPlace_LU",
335                     PCFactorSetUseInPlace_LU);CHKERRQ(ierr);
336   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetMatOrderingType_C","PCFactorSetMatOrderingType_Factor",
337                     PCFactorSetMatOrderingType_Factor);CHKERRQ(ierr);
338   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetReuseOrdering_C","PCFactorSetReuseOrdering_LU",
339                     PCFactorSetReuseOrdering_LU);CHKERRQ(ierr);
340   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetReuseFill_C","PCFactorSetReuseFill_LU",
341                     PCFactorSetReuseFill_LU);CHKERRQ(ierr);
342   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetColumnPivot_C","PCFactorSetColumnPivot_Factor",
343                     PCFactorSetColumnPivot_Factor);CHKERRQ(ierr);
344   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetPivotInBlocks_C","PCFactorSetPivotInBlocks_Factor",
345                     PCFactorSetPivotInBlocks_Factor);CHKERRQ(ierr);
346   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorReorderForNonzeroDiagonal_C","PCFactorReorderForNonzeroDiagonal_LU",
347                     PCFactorReorderForNonzeroDiagonal_LU);CHKERRQ(ierr);
348   PetscFunctionReturn(0);
349 }
350 EXTERN_C_END
351