xref: /petsc/src/ksp/pc/impls/factor/ilu/ilu.c (revision 7a4fe282d1b349e95b3be72d69d8dd3d3bcd7bc6) !
1 #define PETSCKSP_DLL
2 
3 /*
4    Defines a ILU factorization preconditioner for any Mat implementation
5 */
6 #include "../src/ksp/pc/impls/factor/ilu/ilu.h"     /*I "petscpc.h"  I*/
7 
8 /* ------------------------------------------------------------------------------------------*/
9 EXTERN_C_BEGIN
10 #undef __FUNCT__
11 #define __FUNCT__ "PCFactorSetReuseFill_ILU"
12 PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetReuseFill_ILU(PC pc,PetscTruth flag)
13 {
14   PC_ILU *lu = (PC_ILU*)pc->data;
15 
16   PetscFunctionBegin;
17   lu->reusefill = flag;
18   PetscFunctionReturn(0);
19 }
20 EXTERN_C_END
21 
22 EXTERN_C_BEGIN
23 #undef __FUNCT__
24 #define __FUNCT__ "PCFactorReorderForNonzeroDiagonal_ILU"
25 PetscErrorCode PETSCKSP_DLLEXPORT PCFactorReorderForNonzeroDiagonal_ILU(PC pc,PetscReal z)
26 {
27   PC_ILU *ilu = (PC_ILU*)pc->data;
28 
29   PetscFunctionBegin;
30   ilu->nonzerosalongdiagonal = PETSC_TRUE;
31   if (z == PETSC_DECIDE) {
32     ilu->nonzerosalongdiagonaltol = 1.e-10;
33   } else {
34     ilu->nonzerosalongdiagonaltol = z;
35   }
36   PetscFunctionReturn(0);
37 }
38 EXTERN_C_END
39 
40 #undef __FUNCT__
41 #define __FUNCT__ "PCDestroy_ILU_Internal"
42 PetscErrorCode PCDestroy_ILU_Internal(PC pc)
43 {
44   PC_ILU         *ilu = (PC_ILU*)pc->data;
45   PetscErrorCode ierr;
46 
47   PetscFunctionBegin;
48   if (!ilu->inplace && ((PC_Factor*)ilu)->fact) {ierr = MatDestroy(((PC_Factor*)ilu)->fact);CHKERRQ(ierr);}
49   if (ilu->row && ilu->col && ilu->row != ilu->col) {ierr = ISDestroy(ilu->row);CHKERRQ(ierr);}
50   if (ilu->col) {ierr = ISDestroy(ilu->col);CHKERRQ(ierr);}
51   PetscFunctionReturn(0);
52 }
53 
54 EXTERN_C_BEGIN
55 #undef __FUNCT__
56 #define __FUNCT__ "PCFactorSetUseDropTolerance_ILU"
57 PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetUseDropTolerance_ILU(PC pc,PetscReal dt,PetscReal dtcol,PetscInt dtcount)
58 {
59   PC_ILU         *ilu = (PC_ILU*)pc->data;
60   PetscErrorCode ierr;
61 
62   PetscFunctionBegin;
63   if (pc->setupcalled && (!ilu->usedt || ((PC_Factor*)ilu)->info.dt != dt || ((PC_Factor*)ilu)->info.dtcol != dtcol || ((PC_Factor*)ilu)->info.dtcount != dtcount)) {
64     pc->setupcalled   = 0;
65     ierr = PCDestroy_ILU_Internal(pc);CHKERRQ(ierr);
66   }
67   ilu->usedt                      = PETSC_TRUE;
68   ((PC_Factor*)ilu)->info.dt      = dt;
69   ((PC_Factor*)ilu)->info.dtcol   = dtcol;
70   ((PC_Factor*)ilu)->info.dtcount = dtcount;
71   ((PC_Factor*)ilu)->info.fill    = PETSC_DEFAULT;
72   PetscFunctionReturn(0);
73 }
74 EXTERN_C_END
75 
76 EXTERN_C_BEGIN
77 #undef __FUNCT__
78 #define __FUNCT__ "PCFactorSetReuseOrdering_ILU"
79 PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetReuseOrdering_ILU(PC pc,PetscTruth flag)
80 {
81   PC_ILU *ilu = (PC_ILU*)pc->data;
82 
83   PetscFunctionBegin;
84   ilu->reuseordering = flag;
85   PetscFunctionReturn(0);
86 }
87 EXTERN_C_END
88 
89 EXTERN_C_BEGIN
90 #undef __FUNCT__
91 #define __FUNCT__ "PCFactorSetUseInPlace_ILU"
92 PetscErrorCode PETSCKSP_DLLEXPORT PCFactorSetUseInPlace_ILU(PC pc)
93 {
94   PC_ILU *dir = (PC_ILU*)pc->data;
95 
96   PetscFunctionBegin;
97   dir->inplace = PETSC_TRUE;
98   PetscFunctionReturn(0);
99 }
100 EXTERN_C_END
101 
102 #undef __FUNCT__
103 #define __FUNCT__ "PCSetFromOptions_ILU"
104 static PetscErrorCode PCSetFromOptions_ILU(PC pc)
105 {
106   PetscErrorCode ierr;
107   PetscInt       dtmax = 3,itmp;
108   PetscTruth     flg,set;
109   PetscReal      dt[3];
110   char           tname[256];
111   PC_ILU         *ilu = (PC_ILU*)pc->data;
112   PetscFList     ordlist;
113   PetscReal      tol;
114 
115   PetscFunctionBegin;
116   if (!MatOrderingRegisterAllCalled) {ierr = MatOrderingRegisterAll(PETSC_NULL);CHKERRQ(ierr);}
117   ierr = PetscOptionsHead("ILU Options");CHKERRQ(ierr);
118     ierr = PetscOptionsInt("-pc_factor_levels","levels of fill","PCFactorSetLevels",(PetscInt)((PC_Factor*)ilu)->info.levels,&itmp,&flg);CHKERRQ(ierr);
119     if (flg) ((PC_Factor*)ilu)->info.levels = itmp;
120     ierr = PetscOptionsName("-pc_factor_in_place","do factorization in place","PCFactorSetUseInPlace",&flg);CHKERRQ(ierr);
121     if (flg) ilu->inplace = PETSC_TRUE;
122     ierr = PetscOptionsName("-pc_factor_diagonal_fill","Allow fill into empty diagonal entry","PCFactorSetAllowDiagonalFill",&flg);CHKERRQ(ierr);
123     ((PC_Factor*)ilu)->info.diagonal_fill = (double) flg;
124     ierr = PetscOptionsName("-pc_factor_reuse_fill","Reuse fill ratio from previous factorization","PCFactorSetReuseFill",&flg);CHKERRQ(ierr);
125     if (flg) ilu->reusefill = PETSC_TRUE;
126     ierr = PetscOptionsName("-pc_factor_reuse_ordering","Reuse previous reordering","PCFactorSetReuseOrdering",&flg);CHKERRQ(ierr);
127     if (flg) ilu->reuseordering = PETSC_TRUE;
128     ierr = PetscOptionsName("-pc_factor_shift_nonzero","Shift added to diagonal","PCFactorSetShiftNonzero",&flg);CHKERRQ(ierr);
129     if (flg) {
130       ierr = PCFactorSetShiftNonzero(pc,(PetscReal)PETSC_DECIDE);CHKERRQ(ierr);
131     }
132     ierr = PetscOptionsReal("-pc_factor_shift_nonzero","Shift added to diagonal","PCFactorSetShiftNonzero",((PC_Factor*)ilu)->info.shiftnz,&((PC_Factor*)ilu)->info.shiftnz,0);CHKERRQ(ierr);
133     flg = (((PC_Factor*)ilu)->info.shiftpd > 0.0) ? PETSC_TRUE : PETSC_FALSE;
134     ierr = PetscOptionsTruth("-pc_factor_shift_positive_definite","Manteuffel shift applied to diagonal","PCFactorSetShiftPd",flg,&flg,PETSC_NULL);CHKERRQ(ierr);
135     ierr = PCFactorSetShiftPd(pc,flg);CHKERRQ(ierr);
136     ierr = PetscOptionsReal("-pc_factor_zeropivot","Pivot is considered zero if less than","PCFactorSetZeroPivot",((PC_Factor*)ilu)->info.zeropivot,&((PC_Factor*)ilu)->info.zeropivot,0);CHKERRQ(ierr);
137 
138     dt[0] = ((PC_Factor*)ilu)->info.dt;
139     dt[1] = ((PC_Factor*)ilu)->info.dtcol;
140     dt[2] = ((PC_Factor*)ilu)->info.dtcount;
141     ierr = PetscOptionsRealArray("-pc_factor_use_drop_tolerance","<dt,dtcol,maxrowcount>","PCFactorSetUseDropTolerance",dt,&dtmax,&flg);CHKERRQ(ierr);
142     if (flg) {
143       ierr = PCFactorSetUseDropTolerance(pc,dt[0],dt[1],(PetscInt)dt[2]);CHKERRQ(ierr);
144     }
145     ierr = PetscOptionsReal("-pc_factor_fill","Expected fill in factorization","PCFactorSetFill",((PC_Factor*)ilu)->info.fill,&((PC_Factor*)ilu)->info.fill,&flg);CHKERRQ(ierr);
146     ierr = PetscOptionsName("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",&flg);CHKERRQ(ierr);
147     if (flg) {
148       tol = PETSC_DECIDE;
149       ierr = PetscOptionsReal("-pc_factor_nonzeros_along_diagonal","Reorder to remove zeros from diagonal","PCFactorReorderForNonzeroDiagonal",ilu->nonzerosalongdiagonaltol,&tol,0);CHKERRQ(ierr);
150       ierr = PCFactorReorderForNonzeroDiagonal(pc,tol);CHKERRQ(ierr);
151     }
152 
153     ierr = MatGetOrderingList(&ordlist);CHKERRQ(ierr);
154     ierr = PetscOptionsList("-pc_factor_mat_ordering_type","Reorder to reduce nonzeros in ILU","PCFactorSetMatOrderingType",ordlist,((PC_Factor*)ilu)->ordering,tname,256,&flg);CHKERRQ(ierr);
155     if (flg) {
156       ierr = PCFactorSetMatOrderingType(pc,tname);CHKERRQ(ierr);
157     }
158     flg = ((PC_Factor*)ilu)->info.pivotinblocks ? PETSC_TRUE : PETSC_FALSE;
159     ierr = PetscOptionsTruth("-pc_factor_pivot_in_blocks","Pivot inside matrix blocks for BAIJ and SBAIJ","PCFactorSetPivotInBlocks",flg,&flg,&set);CHKERRQ(ierr);
160     if (set) {
161       ierr = PCFactorSetPivotInBlocks(pc,flg);CHKERRQ(ierr);
162     }
163     ierr = PetscOptionsName("-pc_factor_shift_in_blocks","Shift added to diagonal of block","PCFactorSetShiftInBlocks",&flg);CHKERRQ(ierr);
164     if (flg) {
165       ierr = PCFactorSetShiftInBlocks(pc,(PetscReal)PETSC_DECIDE);CHKERRQ(ierr);
166     }
167     ierr = PetscOptionsReal("-pc_factor_shift_in_blocks","Shift added to diagonal of block","PCFactorSetShiftInBlocks",((PC_Factor*)ilu)->info.shiftinblocks,&((PC_Factor*)ilu)->info.shiftinblocks,0);CHKERRQ(ierr);
168 
169   ierr = PetscOptionsTail();CHKERRQ(ierr);
170   PetscFunctionReturn(0);
171 }
172 
173 #undef __FUNCT__
174 #define __FUNCT__ "PCView_ILU"
175 static PetscErrorCode PCView_ILU(PC pc,PetscViewer viewer)
176 {
177   PC_ILU         *ilu = (PC_ILU*)pc->data;
178   PetscErrorCode ierr;
179   PetscTruth     isstring,iascii;
180 
181   PetscFunctionBegin;
182   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_STRING,&isstring);CHKERRQ(ierr);
183   ierr = PetscTypeCompare((PetscObject)viewer,PETSC_VIEWER_ASCII,&iascii);CHKERRQ(ierr);
184   if (iascii) {
185     if (ilu->usedt) {
186         ierr = PetscViewerASCIIPrintf(viewer,"  ILU: drop tolerance %G\n",((PC_Factor*)ilu)->info.dt);CHKERRQ(ierr);
187         ierr = PetscViewerASCIIPrintf(viewer,"  ILU: max nonzeros per row %D\n",(PetscInt)((PC_Factor*)ilu)->info.dtcount);CHKERRQ(ierr);
188         ierr = PetscViewerASCIIPrintf(viewer,"  ILU: column permutation tolerance %G\n",((PC_Factor*)ilu)->info.dtcol);CHKERRQ(ierr);
189     } else if (((PC_Factor*)ilu)->info.levels == 1) {
190         ierr = PetscViewerASCIIPrintf(viewer,"  ILU: %D level of fill\n",(PetscInt)((PC_Factor*)ilu)->info.levels);CHKERRQ(ierr);
191     } else {
192         ierr = PetscViewerASCIIPrintf(viewer,"  ILU: %D levels of fill\n",(PetscInt)((PC_Factor*)ilu)->info.levels);CHKERRQ(ierr);
193     }
194     ierr = PetscViewerASCIIPrintf(viewer,"  ILU: factor fill ratio allocated %G\n",((PC_Factor*)ilu)->info.fill);CHKERRQ(ierr);
195     ierr = PetscViewerASCIIPrintf(viewer,"  ILU: tolerance for zero pivot %G\n",((PC_Factor*)ilu)->info.zeropivot);CHKERRQ(ierr);
196     if (((PC_Factor*)ilu)->info.shiftpd) {ierr = PetscViewerASCIIPrintf(viewer,"  ILU: using Manteuffel shift\n");CHKERRQ(ierr);}
197     if (((PC_Factor*)ilu)->info.shiftnz) {ierr = PetscViewerASCIIPrintf(viewer,"  ILU: using diagonal shift to prevent zero pivot\n");CHKERRQ(ierr);}
198     if (((PC_Factor*)ilu)->info.shiftinblocks) {ierr = PetscViewerASCIIPrintf(viewer,"  ILU: using diagonal shift on blocks to prevent zero pivot\n");CHKERRQ(ierr);}
199     if (ilu->inplace) {ierr = PetscViewerASCIIPrintf(viewer,"       in-place factorization\n");CHKERRQ(ierr);}
200     else              {ierr = PetscViewerASCIIPrintf(viewer,"       out-of-place factorization\n");CHKERRQ(ierr);}
201     ierr = PetscViewerASCIIPrintf(viewer,"       matrix ordering: %s\n",((PC_Factor*)ilu)->ordering);CHKERRQ(ierr);
202     if (ilu->reusefill)     {ierr = PetscViewerASCIIPrintf(viewer,"       Reusing fill from past factorization\n");CHKERRQ(ierr);}
203     if (ilu->reuseordering) {ierr = PetscViewerASCIIPrintf(viewer,"       Reusing reordering from past factorization\n");CHKERRQ(ierr);}
204     if (((PC_Factor*)ilu)->fact) {
205       ierr = PetscViewerASCIIPrintf(viewer,"  ILU: factor fill ratio needed %G\n",ilu->actualfill);CHKERRQ(ierr);
206       ierr = PetscViewerASCIIPrintf(viewer,"       Factored matrix follows\n");CHKERRQ(ierr);
207       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
208       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
209       ierr = PetscViewerASCIIPushTab(viewer);CHKERRQ(ierr);
210       ierr = PetscViewerPushFormat(viewer,PETSC_VIEWER_ASCII_INFO);CHKERRQ(ierr);
211       ierr = MatView(((PC_Factor*)ilu)->fact,viewer);CHKERRQ(ierr);
212       ierr = PetscViewerPopFormat(viewer);CHKERRQ(ierr);
213       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
214       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
215       ierr = PetscViewerASCIIPopTab(viewer);CHKERRQ(ierr);
216     }
217   } else if (isstring) {
218     ierr = PetscViewerStringSPrintf(viewer," lvls=%D,order=%s",(PetscInt)((PC_Factor*)ilu)->info.levels,((PC_Factor*)ilu)->ordering);CHKERRQ(ierr);CHKERRQ(ierr);
219   } else {
220     SETERRQ1(PETSC_ERR_SUP,"Viewer type %s not supported for PCILU",((PetscObject)viewer)->type_name);
221   }
222   PetscFunctionReturn(0);
223 }
224 
225 #undef __FUNCT__
226 #define __FUNCT__ "PCSetUp_ILU"
227 static PetscErrorCode PCSetUp_ILU(PC pc)
228 {
229   PetscErrorCode ierr;
230   PC_ILU         *ilu = (PC_ILU*)pc->data;
231   MatInfo        info;
232 
233   PetscFunctionBegin;
234   if (ilu->inplace) {
235     CHKMEMQ;
236     if (!pc->setupcalled) {
237 
238       /* In-place factorization only makes sense with the natural ordering,
239          so we only need to get the ordering once, even if nonzero structure changes */
240       ierr = MatGetOrdering(pc->pmat,((PC_Factor*)ilu)->ordering,&ilu->row,&ilu->col);CHKERRQ(ierr);
241       if (ilu->row) {ierr = PetscLogObjectParent(pc,ilu->row);CHKERRQ(ierr);}
242       if (ilu->col) {ierr = PetscLogObjectParent(pc,ilu->col);CHKERRQ(ierr);}
243     }
244 
245     /* In place ILU only makes sense with fill factor of 1.0 because
246        cannot have levels of fill */
247     ((PC_Factor*)ilu)->info.fill          = 1.0;
248     ((PC_Factor*)ilu)->info.diagonal_fill = 0;
249     ierr = MatILUFactor(pc->pmat,ilu->row,ilu->col,&((PC_Factor*)ilu)->info);CHKERRQ(ierr);
250     CHKMEMQ;
251     ((PC_Factor*)ilu)->fact = pc->pmat;
252   } else if (ilu->usedt) {
253     if (!pc->setupcalled) {
254       ierr = MatGetOrdering(pc->pmat,((PC_Factor*)ilu)->ordering,&ilu->row,&ilu->col);CHKERRQ(ierr);
255     CHKMEMQ;
256       if (ilu->row) {ierr = PetscLogObjectParent(pc,ilu->row);CHKERRQ(ierr);}
257       if (ilu->col) {ierr = PetscLogObjectParent(pc,ilu->col);CHKERRQ(ierr);}
258       ierr = MatILUDTFactor(pc->pmat,ilu->row,ilu->col,&((PC_Factor*)ilu)->info,&((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
259       ierr = PetscLogObjectParent(pc,((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
260     } else if (pc->flag != SAME_NONZERO_PATTERN) {
261     CHKMEMQ;
262       ierr = MatDestroy(((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
263     CHKMEMQ;
264       if (!ilu->reuseordering) {
265         if (ilu->row) {ierr = ISDestroy(ilu->row);CHKERRQ(ierr);}
266         if (ilu->col) {ierr = ISDestroy(ilu->col);CHKERRQ(ierr);}
267         ierr = MatGetOrdering(pc->pmat,((PC_Factor*)ilu)->ordering,&ilu->row,&ilu->col);CHKERRQ(ierr);
268         if (ilu->row) {ierr = PetscLogObjectParent(pc,ilu->row);CHKERRQ(ierr);}
269         if (ilu->col) {ierr = PetscLogObjectParent(pc,ilu->col);CHKERRQ(ierr);}
270       }
271       ierr = MatILUDTFactor(pc->pmat,ilu->row,ilu->col,&((PC_Factor*)ilu)->info,&((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
272       ierr = PetscLogObjectParent(pc,((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
273     } else if (!ilu->reusefill) {
274       ierr = MatDestroy(((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
275       ierr = MatILUDTFactor(pc->pmat,ilu->row,ilu->col,&((PC_Factor*)ilu)->info,&((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
276       ierr = PetscLogObjectParent(pc,((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
277     } else {
278       ierr = MatLUFactorNumeric(((PC_Factor*)ilu)->fact,pc->pmat,&((PC_Factor*)ilu)->info);CHKERRQ(ierr);
279     }
280   } else {
281     if (!pc->setupcalled) {
282       /* first time in so compute reordering and symbolic factorization */
283       ierr = MatGetOrdering(pc->pmat,((PC_Factor*)ilu)->ordering,&ilu->row,&ilu->col);CHKERRQ(ierr);
284       if (ilu->row) {ierr = PetscLogObjectParent(pc,ilu->row);CHKERRQ(ierr);}
285       if (ilu->col) {ierr = PetscLogObjectParent(pc,ilu->col);CHKERRQ(ierr);}
286       /*  Remove zeros along diagonal?     */
287       if (ilu->nonzerosalongdiagonal) {
288         ierr = MatReorderForNonzeroDiagonal(pc->pmat,ilu->nonzerosalongdiagonaltol,ilu->row,ilu->col);CHKERRQ(ierr);
289       }
290     CHKMEMQ;
291       ierr = MatGetFactor(pc->pmat,MAT_SOLVER_PETSC,MAT_FACTOR_ILU,&((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
292     CHKMEMQ;
293       ierr = MatILUFactorSymbolic(((PC_Factor*)ilu)->fact,pc->pmat,ilu->row,ilu->col,&((PC_Factor*)ilu)->info);CHKERRQ(ierr);
294       ierr = MatGetInfo(((PC_Factor*)ilu)->fact,MAT_LOCAL,&info);CHKERRQ(ierr);
295       ilu->actualfill = info.fill_ratio_needed;
296       ierr = PetscLogObjectParent(pc,((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
297     } else if (pc->flag != SAME_NONZERO_PATTERN) {
298       if (!ilu->reuseordering) {
299         /* compute a new ordering for the ILU */
300         ierr = ISDestroy(ilu->row);CHKERRQ(ierr);
301         ierr = ISDestroy(ilu->col);CHKERRQ(ierr);
302         ierr = MatGetOrdering(pc->pmat,((PC_Factor*)ilu)->ordering,&ilu->row,&ilu->col);CHKERRQ(ierr);
303         if (ilu->row) {ierr = PetscLogObjectParent(pc,ilu->row);CHKERRQ(ierr);}
304         if (ilu->col) {ierr = PetscLogObjectParent(pc,ilu->col);CHKERRQ(ierr);}
305         /*  Remove zeros along diagonal?     */
306         if (ilu->nonzerosalongdiagonal) {
307           ierr = MatReorderForNonzeroDiagonal(pc->pmat,ilu->nonzerosalongdiagonaltol,ilu->row,ilu->col);CHKERRQ(ierr);
308         }
309       }
310       ierr = MatDestroy(((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
311       ierr = MatGetFactor(pc->pmat,MAT_SOLVER_PETSC,MAT_FACTOR_ILU,&((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
312       ierr = MatILUFactorSymbolic(((PC_Factor*)ilu)->fact,pc->pmat,ilu->row,ilu->col,&((PC_Factor*)ilu)->info);CHKERRQ(ierr);
313       ierr = MatGetInfo(((PC_Factor*)ilu)->fact,MAT_LOCAL,&info);CHKERRQ(ierr);
314       ilu->actualfill = info.fill_ratio_needed;
315       ierr = PetscLogObjectParent(pc,((PC_Factor*)ilu)->fact);CHKERRQ(ierr);
316     }
317     CHKMEMQ;
318     ierr = MatLUFactorNumeric(((PC_Factor*)ilu)->fact,pc->pmat,&((PC_Factor*)ilu)->info);CHKERRQ(ierr);
319     CHKMEMQ;
320   }
321   PetscFunctionReturn(0);
322 }
323 
324 #undef __FUNCT__
325 #define __FUNCT__ "PCDestroy_ILU"
326 static PetscErrorCode PCDestroy_ILU(PC pc)
327 {
328   PC_ILU         *ilu = (PC_ILU*)pc->data;
329   PetscErrorCode ierr;
330 
331   PetscFunctionBegin;
332   ierr = PCDestroy_ILU_Internal(pc);CHKERRQ(ierr);
333   ierr = PetscStrfree(((PC_Factor*)ilu)->ordering);CHKERRQ(ierr);
334   ierr = PetscFree(ilu);CHKERRQ(ierr);
335   PetscFunctionReturn(0);
336 }
337 
338 #undef __FUNCT__
339 #define __FUNCT__ "PCApply_ILU"
340 static PetscErrorCode PCApply_ILU(PC pc,Vec x,Vec y)
341 {
342   PC_ILU         *ilu = (PC_ILU*)pc->data;
343   PetscErrorCode ierr;
344 
345   PetscFunctionBegin;
346   ierr = MatSolve(((PC_Factor*)ilu)->fact,x,y);CHKERRQ(ierr);
347   PetscFunctionReturn(0);
348 }
349 
350 #undef __FUNCT__
351 #define __FUNCT__ "PCApplyTranspose_ILU"
352 static PetscErrorCode PCApplyTranspose_ILU(PC pc,Vec x,Vec y)
353 {
354   PC_ILU         *ilu = (PC_ILU*)pc->data;
355   PetscErrorCode ierr;
356 
357   PetscFunctionBegin;
358   ierr = MatSolveTranspose(((PC_Factor*)ilu)->fact,x,y);CHKERRQ(ierr);
359   PetscFunctionReturn(0);
360 }
361 
362 /*MC
363      PCILU - Incomplete factorization preconditioners.
364 
365    Options Database Keys:
366 +  -pc_factor_levels <k> - number of levels of fill for ILU(k)
367 .  -pc_factor_in_place - only for ILU(0) with natural ordering, reuses the space of the matrix for
368                       its factorization (overwrites original matrix)
369 .  -pc_factor_diagonal_fill - fill in a zero diagonal even if levels of fill indicate it wouldn't be fill
370 .  -pc_factor_reuse_ordering - reuse ordering of factorized matrix from previous factorization
371 .  -pc_factor_use_drop_tolerance <dt,dtcol,maxrowcount> - use Saad's drop tolerance ILUdt
372 .  -pc_factor_fill <nfill> - expected amount of fill in factored matrix compared to original matrix, nfill > 1
373 .  -pc_factor_nonzeros_along_diagonal - reorder the matrix before factorization to remove zeros from the diagonal,
374                                    this decreases the chance of getting a zero pivot
375 .  -pc_factor_mat_ordering_type <natural,nd,1wd,rcm,qmd> - set the row/column ordering of the factored matrix
376 .  -pc_factor_pivot_in_blocks - for block ILU(k) factorization, i.e. with BAIJ matrices with block size larger
377                              than 1 the diagonal blocks are factored with partial pivoting (this increases the
378                              stability of the ILU factorization
379 .  -pc_factor_shift_in_blocks - adds a small diagonal to any block if it is singular during ILU factorization
380 .  -pc_factor_shift_nonzero <shift> - Sets shift amount or PETSC_DECIDE for the default
381 -  -pc_factor_shift_positive_definite [PETSC_TRUE/PETSC_FALSE] - Activate/Deactivate PCFactorSetShiftPd(); the value
382    is optional with PETSC_TRUE being the default
383 
384    Level: beginner
385 
386   Concepts: incomplete factorization
387 
388    Notes: Only implemented for some matrix formats. (for parallel use you
389              must use MATMPIROWBS, see MatCreateMPIRowbs(), this supports only ILU(0) and this is not recommended
390              unless you really want a parallel ILU).
391 
392           For BAIJ matrices this implements a point block ILU
393 
394    References:
395    T. Dupont, R. Kendall, and H. Rachford. An approximate factorization procedure for solving
396    self-adjoint elliptic difference equations. SIAM J. Numer. Anal., 5:559--573, 1968.
397 
398    T.A. Oliphant. An implicit numerical method for solving two-dimensional time-dependent dif-
399    fusion problems. Quart. Appl. Math., 19:221--229, 1961.
400 
401    Review article: APPROXIMATE AND INCOMPLETE FACTORIZATIONS, TONY F. CHAN AND HENK A. VAN DER VORST
402       http://igitur-archive.library.uu.nl/math/2001-0621-115821/proc.pdf chapter in Parallel Numerical
403       Algorithms, edited by D. Keyes, A. Semah, V. Venkatakrishnan, ICASE/LaRC Interdisciplinary Series in
404       Science and Engineering, Kluwer, pp. 167--202.
405 
406 
407 .seealso:  PCCreate(), PCSetType(), PCType (for list of available types), PC, PCSOR, MatOrderingType,
408            PCFactorSetZeroPivot(), PCFactorSetShiftNonzero(), PCFactorSetShiftPd(), PCFactorSetUseDropTolerance(),
409            PCFactorSetFill(), PCFactorSetMatOrderingType(), PCFactorSetReuseOrdering(),
410            PCFactorSetLevels(), PCFactorSetUseInPlace(), PCFactorSetAllowDiagonalFill(), PCFactorSetPivotInBlocks(),
411            PCFactorSetShiftNonzero(),PCFactorSetShiftPd()
412 
413 M*/
414 
415 EXTERN_C_BEGIN
416 #undef __FUNCT__
417 #define __FUNCT__ "PCCreate_ILU"
418 PetscErrorCode PETSCKSP_DLLEXPORT PCCreate_ILU(PC pc)
419 {
420   PetscErrorCode ierr;
421   PC_ILU         *ilu;
422 
423   PetscFunctionBegin;
424   ierr = PetscNewLog(pc,PC_ILU,&ilu);CHKERRQ(ierr);
425 
426   ((PC_Factor*)ilu)->fact                    = 0;
427   ierr = MatFactorInfoInitialize(&((PC_Factor*)ilu)->info);CHKERRQ(ierr);
428   ((PC_Factor*)ilu)->info.levels             = 0;
429   ((PC_Factor*)ilu)->info.fill               = 1.0;
430   ilu->col                     = 0;
431   ilu->row                     = 0;
432   ilu->inplace                 = PETSC_FALSE;
433   ierr = PetscStrallocpy(MATORDERING_NATURAL,&((PC_Factor*)ilu)->ordering);CHKERRQ(ierr);
434   ilu->reuseordering           = PETSC_FALSE;
435   ilu->usedt                   = PETSC_FALSE;
436   ((PC_Factor*)ilu)->info.dt                 = PETSC_DEFAULT;
437   ((PC_Factor*)ilu)->info.dtcount            = PETSC_DEFAULT;
438   ((PC_Factor*)ilu)->info.dtcol              = PETSC_DEFAULT;
439   ((PC_Factor*)ilu)->info.shiftnz            = 1.e-12;
440   ((PC_Factor*)ilu)->info.shiftpd            = 0.0; /* false */
441   ((PC_Factor*)ilu)->info.zeropivot          = 1.e-12;
442   ((PC_Factor*)ilu)->info.pivotinblocks      = 1.0;
443   ((PC_Factor*)ilu)->info.shiftinblocks      = 1.e-12;
444   ilu->reusefill               = PETSC_FALSE;
445   ((PC_Factor*)ilu)->info.diagonal_fill      = 0;
446   pc->data                     = (void*)ilu;
447 
448   pc->ops->destroy             = PCDestroy_ILU;
449   pc->ops->apply               = PCApply_ILU;
450   pc->ops->applytranspose      = PCApplyTranspose_ILU;
451   pc->ops->setup               = PCSetUp_ILU;
452   pc->ops->setfromoptions      = PCSetFromOptions_ILU;
453   pc->ops->getfactoredmatrix   = PCFactorGetMatrix_Factor;
454   pc->ops->view                = PCView_ILU;
455   pc->ops->applyrichardson     = 0;
456 
457   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetZeroPivot_C","PCFactorSetZeroPivot_Factor",
458                     PCFactorSetZeroPivot_Factor);CHKERRQ(ierr);
459   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftNonzero_C","PCFactorSetShiftNonzero_Factor",
460                     PCFactorSetShiftNonzero_Factor);CHKERRQ(ierr);
461   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftPd_C","PCFactorSetShiftPd_Factor",
462                     PCFactorSetShiftPd_Factor);CHKERRQ(ierr);
463 
464   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorGetMatSolverPackage_C","PCFactorGetMatSolverPackage_Factor",
465                     PCFactorGetMatSolverPackage_Factor);CHKERRQ(ierr);
466   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetUseDropTolerance_C","PCFactorSetUseDropTolerance_ILU",
467                     PCFactorSetUseDropTolerance_ILU);CHKERRQ(ierr);
468   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetFill_C","PCFactorSetFill_Factor",
469                     PCFactorSetFill_Factor);CHKERRQ(ierr);
470   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetMatOrderingType_C","PCFactorSetMatOrderingType_Factor",
471                     PCFactorSetMatOrderingType_Factor);CHKERRQ(ierr);
472   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetReuseOrdering_C","PCFactorSetReuseOrdering_ILU",
473                     PCFactorSetReuseOrdering_ILU);CHKERRQ(ierr);
474   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetReuseFill_C","PCFactorSetReuseFill_ILU",
475                     PCFactorSetReuseFill_ILU);CHKERRQ(ierr);
476   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetLevels_C","PCFactorSetLevels_Factor",
477                     PCFactorSetLevels_Factor);CHKERRQ(ierr);
478   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetUseInPlace_C","PCFactorSetUseInPlace_ILU",
479                     PCFactorSetUseInPlace_ILU);CHKERRQ(ierr);
480   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetAllowDiagonalFill_C","PCFactorSetAllowDiagonalFill_Factor",
481                     PCFactorSetAllowDiagonalFill_Factor);CHKERRQ(ierr);
482   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetPivotInBlocks_C","PCFactorSetPivotInBlocks_Factor",
483                     PCFactorSetPivotInBlocks_Factor);CHKERRQ(ierr);
484   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorSetShiftInBlocks_C","PCFactorSetShiftInBlocks_Factor",
485                     PCFactorSetShiftInBlocks_Factor);CHKERRQ(ierr);
486   ierr = PetscObjectComposeFunctionDynamic((PetscObject)pc,"PCFactorReorderForNonzeroDiagonal_C","PCFactorReorderForNonzeroDiagonal_ILU",
487                     PCFactorReorderForNonzeroDiagonal_ILU);CHKERRQ(ierr);
488   PetscFunctionReturn(0);
489 }
490 EXTERN_C_END
491