MatSetUnfactored
Resets a factored matrix to be treated as unfactored.
Synopsis
int MatSetUnfactored(Mat mat)
Collective on
Mat
Input Parameter
mat -the factored matrix to be reset
Notes
This routine should be used only with factored matrices formed by in-
placefactorization via ILU(0) (or by in-place LU factorization for the
MATSEQDENSEformat). This option can save memory, for example, when solving
nonlinearsystems with a matrix-free Newton-Krylov method and a matrix-based, in-
placeILU(0) preconditioner.
Note that one can specify in-place ILU(0) factorization by
calling
PCType(pc,PCILU);
PCILUSeUseInPlace(pc);
or by using the options -pc_type ilu -
pc_ilu_in_place
In-place factorization ILU(0) can also be used as a
localsolver for the blocks within the block Jacobi or additive
Schwarzmethods (runtime option: -sub_pc_ilu_in_place). See the
discussionof these preconditioners in the users manual for details on
settinglocal solver options.
See Also
PCILUSetUseInPlace(), PCLUSetUseInPlace()
Keywords
matrix-free, in-place ILU, in-place LU
Location: src/mat/interface/matrix.c
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