Actual source code: factor.c

petsc-master 2014-11-25
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  2: #include <../src/ksp/pc/impls/factor/factor.h>  /*I "petscpc.h" I*/

  6: /*@
  7:     PCFactorSetUpMatSolverPackage - Can be called after KSPSetOperators() or PCSetOperators(), causes MatGetFactor() to be called so then one may
  8:        set the options for that particular factorization object.

 10:   Input Parameter:
 11: .  pc  - the preconditioner context

 13:   Notes: After you have called this function (which has to be after the KSPSetOperators() or PCSetOperators()) you can call PCFactorGetMatrix() and then set factor options on that matrix.

 15: .seealso: PCFactorSetMatSolverPackage(), PCFactorGetMatrix()

 17:   Level: intermediate

 19: @*/
 20: PetscErrorCode PCFactorSetUpMatSolverPackage(PC pc)
 21: {

 26:   PetscTryMethod(pc,"PCFactorSetUpMatSolverPackage_C",(PC),(pc));
 27:   return(0);
 28: }

 32: /*@
 33:    PCFactorSetZeroPivot - Sets the size at which smaller pivots are declared to be zero

 35:    Logically Collective on PC

 37:    Input Parameters:
 38: +  pc - the preconditioner context
 39: -  zero - all pivots smaller than this will be considered zero

 41:    Options Database Key:
 42: .  -pc_factor_zeropivot <zero> - Sets tolerance for what is considered a zero pivot

 44:    Level: intermediate

 46: .keywords: PC, set, factorization, direct, fill

 48: .seealso: PCFactorSetShiftType(), PCFactorSetShiftAmount()
 49: @*/
 50: PetscErrorCode  PCFactorSetZeroPivot(PC pc,PetscReal zero)
 51: {

 57:   PetscTryMethod(pc,"PCFactorSetZeroPivot_C",(PC,PetscReal),(pc,zero));
 58:   return(0);
 59: }

 63: /*@
 64:    PCFactorSetShiftType - adds a particular type of quantity to the diagonal of the matrix during
 65:      numerical factorization, thus the matrix has nonzero pivots

 67:    Logically Collective on PC

 69:    Input Parameters:
 70: +  pc - the preconditioner context
 71: -  shifttype - type of shift; one of MAT_SHIFT_NONE, MAT_SHIFT_NONZERO,  MAT_SHIFT_POSITIVE_DEFINITE, MAT_SHIFT_INBLOCKS

 73:    Options Database Key:
 74: .  -pc_factor_shift_type <shifttype> - Sets shift type or PETSC_DECIDE for the default; use '-help' for a list of available types

 76:    Level: intermediate

 78: .keywords: PC, set, factorization,

 80: .seealso: PCFactorSetZeroPivot(), PCFactorSetShiftAmount()
 81: @*/
 82: PetscErrorCode  PCFactorSetShiftType(PC pc,MatFactorShiftType shifttype)
 83: {

 89:   PetscTryMethod(pc,"PCFactorSetShiftType_C",(PC,MatFactorShiftType),(pc,shifttype));
 90:   return(0);
 91: }

 95: /*@
 96:    PCFactorSetShiftAmount - adds a quantity to the diagonal of the matrix during
 97:      numerical factorization, thus the matrix has nonzero pivots

 99:    Logically Collective on PC

101:    Input Parameters:
102: +  pc - the preconditioner context
103: -  shiftamount - amount of shift

105:    Options Database Key:
106: .  -pc_factor_shift_amount <shiftamount> - Sets shift amount or PETSC_DECIDE for the default

108:    Level: intermediate

110: .keywords: PC, set, factorization,

112: .seealso: PCFactorSetZeroPivot(), PCFactorSetShiftType()
113: @*/
114: PetscErrorCode  PCFactorSetShiftAmount(PC pc,PetscReal shiftamount)
115: {

121:   PetscTryMethod(pc,"PCFactorSetShiftAmount_C",(PC,PetscReal),(pc,shiftamount));
122:   return(0);
123: }

127: /*
128:    PCFactorSetDropTolerance - The preconditioner will use an ILU
129:    based on a drop tolerance. (Under development)

131:    Logically Collective on PC

133:    Input Parameters:
134: +  pc - the preconditioner context
135: .  dt - the drop tolerance, try from 1.e-10 to .1
136: .  dtcol - tolerance for column pivot, good values [0.1 to 0.01]
137: -  maxrowcount - the max number of nonzeros allowed in a row, best value
138:                  depends on the number of nonzeros in row of original matrix

140:    Options Database Key:
141: .  -pc_factor_drop_tolerance <dt,dtcol,maxrowcount> - Sets drop tolerance

143:    Level: intermediate

145:       There are NO default values for the 3 parameters, you must set them with reasonable values for your
146:       matrix. We don't know how to compute reasonable values.

148: .keywords: PC, levels, reordering, factorization, incomplete, ILU
149: */
150: PetscErrorCode  PCFactorSetDropTolerance(PC pc,PetscReal dt,PetscReal dtcol,PetscInt maxrowcount)
151: {

158:   PetscTryMethod(pc,"PCFactorSetDropTolerance_C",(PC,PetscReal,PetscReal,PetscInt),(pc,dt,dtcol,maxrowcount));
159:   return(0);
160: }

164: /*@
165:    PCFactorGetLevels - Gets the number of levels of fill to use.

167:    Logically Collective on PC

169:    Input Parameters:
170: .  pc - the preconditioner context

172:    Output Parameter:
173: .  levels - number of levels of fill

175:    Level: intermediate

177: .keywords: PC, levels, fill, factorization, incomplete, ILU
178: @*/
179: PetscErrorCode  PCFactorGetLevels(PC pc,PetscInt *levels)
180: {

185:   PetscUseMethod(pc,"PCFactorGetLevels_C",(PC,PetscInt*),(pc,levels));
186:   return(0);
187: }

191: /*@
192:    PCFactorSetLevels - Sets the number of levels of fill to use.

194:    Logically Collective on PC

196:    Input Parameters:
197: +  pc - the preconditioner context
198: -  levels - number of levels of fill

200:    Options Database Key:
201: .  -pc_factor_levels <levels> - Sets fill level

203:    Level: intermediate

205: .keywords: PC, levels, fill, factorization, incomplete, ILU
206: @*/
207: PetscErrorCode  PCFactorSetLevels(PC pc,PetscInt levels)
208: {

213:   if (levels < 0) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"negative levels");
215:   PetscTryMethod(pc,"PCFactorSetLevels_C",(PC,PetscInt),(pc,levels));
216:   return(0);
217: }

221: /*@
222:    PCFactorSetAllowDiagonalFill - Causes all diagonal matrix entries to be
223:    treated as level 0 fill even if there is no non-zero location.

225:    Logically Collective on PC

227:    Input Parameters:
228: +  pc - the preconditioner context
229: -  flg - PETSC_TRUE to turn on, PETSC_FALSE to turn off

231:    Options Database Key:
232: .  -pc_factor_diagonal_fill

234:    Notes:
235:    Does not apply with 0 fill.

237:    Level: intermediate

239: .keywords: PC, levels, fill, factorization, incomplete, ILU

241: .seealso: PCFactorGetAllowDiagonalFill()

243: @*/
244: PetscErrorCode  PCFactorSetAllowDiagonalFill(PC pc,PetscBool flg)
245: {

250:   PetscTryMethod(pc,"PCFactorSetAllowDiagonalFill_C",(PC,PetscBool),(pc,flg));
251:   return(0);
252: }

256: /*@
257:    PCFactorGetAllowDiagonalFill - Determines if all diagonal matrix entries are
258:        treated as level 0 fill even if there is no non-zero location.

260:    Logically Collective on PC

262:    Input Parameter:
263: .  pc - the preconditioner context

265:    Output Parameter:
266: .   flg - PETSC_TRUE to turn on, PETSC_FALSE to turn off

268:    Options Database Key:
269: .  -pc_factor_diagonal_fill

271:    Notes:
272:    Does not apply with 0 fill.

274:    Level: intermediate

276: .keywords: PC, levels, fill, factorization, incomplete, ILU

278: .seealso: PCFactorSetAllowDiagonalFill()

280: @*/
281: PetscErrorCode  PCFactorGetAllowDiagonalFill(PC pc,PetscBool *flg)
282: {

287:   PetscUseMethod(pc,"PCFactorGetAllowDiagonalFill_C",(PC,PetscBool*),(pc,flg));
288:   return(0);
289: }

293: /*@
294:    PCFactorReorderForNonzeroDiagonal - reorders rows/columns of matrix to remove zeros from diagonal

296:    Logically Collective on PC

298:    Input Parameters:
299: +  pc - the preconditioner context
300: -  tol - diagonal entries smaller than this in absolute value are considered zero

302:    Options Database Key:
303: .  -pc_factor_nonzeros_along_diagonal <tol>

305:    Level: intermediate

307: .keywords: PC, set, factorization, direct, fill

309: .seealso: PCFactorSetFill(), PCFactorSetShiftNonzero(), PCFactorSetZeroPivot(), MatReorderForNonzeroDiagonal()
310: @*/
311: PetscErrorCode  PCFactorReorderForNonzeroDiagonal(PC pc,PetscReal rtol)
312: {

318:   PetscTryMethod(pc,"PCFactorReorderForNonzeroDiagonal_C",(PC,PetscReal),(pc,rtol));
319:   return(0);
320: }

324: /*@C
325:    PCFactorSetMatSolverPackage - sets the software that is used to perform the factorization

327:    Logically Collective on PC

329:    Input Parameters:
330: +  pc - the preconditioner context
331: -  stype - for example, superlu, superlu_dist

333:    Options Database Key:
334: .  -pc_factor_mat_solver_package <stype> - petsc, superlu, superlu_dist, mumps, cusparse

336:    Level: intermediate

338:    Note:
339:      By default this will use the PETSc factorization if it exists


342: .keywords: PC, set, factorization, direct, fill

344: .seealso: MatGetFactor(), MatSolverPackage, PCFactorGetMatSolverPackage()

346: @*/
347: PetscErrorCode  PCFactorSetMatSolverPackage(PC pc,const MatSolverPackage stype)
348: {

353:   PetscTryMethod(pc,"PCFactorSetMatSolverPackage_C",(PC,const MatSolverPackage),(pc,stype));
354:   return(0);
355: }

359: /*@C
360:    PCFactorGetMatSolverPackage - gets the software that is used to perform the factorization

362:    Not Collective

364:    Input Parameter:
365: .  pc - the preconditioner context

367:    Output Parameter:
368: .   stype - for example, superlu, superlu_dist (NULL if the PC does not have a solver package)

370:    Level: intermediate


373: .keywords: PC, set, factorization, direct, fill

375: .seealso: MatGetFactor(), MatSolverPackage, PCFactorGetMatSolverPackage()

377: @*/
378: PetscErrorCode  PCFactorGetMatSolverPackage(PC pc,const MatSolverPackage *stype)
379: {
380:   PetscErrorCode ierr,(*f)(PC,const MatSolverPackage*);

384:   PetscObjectQueryFunction((PetscObject)pc,"PCFactorGetMatSolverPackage_C",&f);
385:   if (f) {
386:     (*f)(pc,stype);
387:   } else {
388:     *stype = NULL;
389:   }
390:   return(0);
391: }

395: /*@
396:    PCFactorSetFill - Indicate the amount of fill you expect in the factored matrix,
397:    fill = number nonzeros in factor/number nonzeros in original matrix.

399:    Not Collective, each process can expect a different amount of fill

401:    Input Parameters:
402: +  pc - the preconditioner context
403: -  fill - amount of expected fill

405:    Options Database Key:
406: .  -pc_factor_fill <fill> - Sets fill amount

408:    Level: intermediate

410:    Note:
411:    For sparse matrix factorizations it is difficult to predict how much
412:    fill to expect. By running with the option -info PETSc will print the
413:    actual amount of fill used; allowing you to set the value accurately for
414:    future runs. Default PETSc uses a value of 5.0

416:    This parameter has NOTHING to do with the levels-of-fill of ILU(). That is set with PCFactorSetLevels() or -pc_factor_levels.


419: .keywords: PC, set, factorization, direct, fill

421: @*/
422: PetscErrorCode  PCFactorSetFill(PC pc,PetscReal fill)
423: {

428:   if (fill < 1.0) SETERRQ(PetscObjectComm((PetscObject)pc),PETSC_ERR_ARG_OUTOFRANGE,"Fill factor cannot be less then 1.0");
429:   PetscTryMethod(pc,"PCFactorSetFill_C",(PC,PetscReal),(pc,fill));
430:   return(0);
431: }

435: /*@
436:    PCFactorSetUseInPlace - Tells the system to do an in-place factorization.
437:    For dense matrices, this enables the solution of much larger problems.
438:    For sparse matrices the factorization cannot be done truly in-place
439:    so this does not save memory during the factorization, but after the matrix
440:    is factored, the original unfactored matrix is freed, thus recovering that
441:    space.

443:    Logically Collective on PC

445:    Input Parameters:
446: +  pc - the preconditioner context
447: -  flg - PETSC_TRUE to enable, PETSC_FALSE to disable

449:    Options Database Key:
450: .  -pc_factor_in_place <true,false>- Activate/deactivate in-place factorization

452:    Notes:
453:    PCFactorSetUseInplace() can only be used with the KSP method KSPPREONLY or when
454:    a different matrix is provided for the multiply and the preconditioner in
455:    a call to KSPSetOperators().
456:    This is because the Krylov space methods require an application of the
457:    matrix multiplication, which is not possible here because the matrix has
458:    been factored in-place, replacing the original matrix.

460:    Level: intermediate

462: .keywords: PC, set, factorization, direct, inplace, in-place, LU

464: .seealso: PCFactorGetUseInPlace()
465: @*/
466: PetscErrorCode  PCFactorSetUseInPlace(PC pc,PetscBool flg)
467: {

472:   PetscTryMethod(pc,"PCFactorSetUseInPlace_C",(PC,PetscBool),(pc,flg));
473:   return(0);
474: }

478: /*@
479:    PCFactorGetUseInPlace - Determines if an in-place factorization is being used.

481:    Logically Collective on PC

483:    Input Parameter:
484: .  pc - the preconditioner context

486:    Output Parameter:
487: .  flg - PETSC_TRUE to enable, PETSC_FALSE to disable

489:    Level: intermediate

491: .keywords: PC, set, factorization, direct, inplace, in-place, LU

493: .seealso: PCFactorSetUseInPlace()
494: @*/
495: PetscErrorCode  PCFactorGetUseInPlace(PC pc,PetscBool *flg)
496: {

501:   PetscUseMethod(pc,"PCFactorGetUseInPlace_C",(PC,PetscBool*),(pc,flg));
502:   return(0);
503: }

507: /*@C
508:     PCFactorSetMatOrderingType - Sets the ordering routine (to reduce fill) to
509:     be used in the LU factorization.

511:     Logically Collective on PC

513:     Input Parameters:
514: +   pc - the preconditioner context
515: -   ordering - the matrix ordering name, for example, MATORDERINGND or MATORDERINGRCM

517:     Options Database Key:
518: .   -pc_factor_mat_ordering_type <nd,rcm,...> - Sets ordering routine

520:     Level: intermediate

522:     Notes: nested dissection is used by default

524:     For Cholesky and ICC and the SBAIJ format reorderings are not available,
525:     since only the upper triangular part of the matrix is stored. You can use the
526:     SeqAIJ format in this case to get reorderings.

528: @*/
529: PetscErrorCode  PCFactorSetMatOrderingType(PC pc,MatOrderingType ordering)
530: {

535:   PetscTryMethod(pc,"PCFactorSetMatOrderingType_C",(PC,MatOrderingType),(pc,ordering));
536:   return(0);
537: }

541: /*@
542:     PCFactorSetColumnPivot - Determines when column pivoting is done during matrix factorization.
543:       For PETSc dense matrices column pivoting is always done, for PETSc sparse matrices
544:       it is never done. For the MATLAB and SuperLU factorization this is used.

546:     Logically Collective on PC

548:     Input Parameters:
549: +   pc - the preconditioner context
550: -   dtcol - 0.0 implies no pivoting, 1.0 complete pivoting (slower, requires more memory but more stable)

552:     Options Database Key:
553: .   -pc_factor_pivoting <dtcol>

555:     Level: intermediate

557: .seealso: PCILUSetMatOrdering(), PCFactorSetPivotInBlocks()
558: @*/
559: PetscErrorCode  PCFactorSetColumnPivot(PC pc,PetscReal dtcol)
560: {

566:   PetscTryMethod(pc,"PCFactorSetColumnPivot_C",(PC,PetscReal),(pc,dtcol));
567:   return(0);
568: }

572: /*@
573:     PCFactorSetPivotInBlocks - Determines if pivoting is done while factoring each block
574:       with BAIJ or SBAIJ matrices

576:     Logically Collective on PC

578:     Input Parameters:
579: +   pc - the preconditioner context
580: -   pivot - PETSC_TRUE or PETSC_FALSE

582:     Options Database Key:
583: .   -pc_factor_pivot_in_blocks <true,false>

585:     Level: intermediate

587: .seealso: PCILUSetMatOrdering(), PCFactorSetColumnPivot()
588: @*/
589: PetscErrorCode  PCFactorSetPivotInBlocks(PC pc,PetscBool pivot)
590: {

596:   PetscTryMethod(pc,"PCFactorSetPivotInBlocks_C",(PC,PetscBool),(pc,pivot));
597:   return(0);
598: }

602: /*@
603:    PCFactorSetReuseFill - When matrices with same different nonzero structure are factored,
604:    this causes later ones to use the fill ratio computed in the initial factorization.

606:    Logically Collective on PC

608:    Input Parameters:
609: +  pc - the preconditioner context
610: -  flag - PETSC_TRUE to reuse else PETSC_FALSE

612:    Options Database Key:
613: .  -pc_factor_reuse_fill - Activates PCFactorSetReuseFill()

615:    Level: intermediate

617: .keywords: PC, levels, reordering, factorization, incomplete, Cholesky

619: .seealso: PCFactorSetReuseOrdering()
620: @*/
621: PetscErrorCode  PCFactorSetReuseFill(PC pc,PetscBool flag)
622: {

628:   PetscTryMethod(pc,"PCFactorSetReuseFill_C",(PC,PetscBool),(pc,flag));
629:   return(0);
630: }