MatGetFactor

Returns a matrix suitable to calls to MatXXFactorSymbolic()

Synopsis

#include "petscmat.h" 
PetscErrorCode MatGetFactor(Mat mat, MatSolverType type, MatFactorType ftype, Mat *f)

Collective

Input Parameters

• mat - the matrix

• type - name of solver type, for example, superlu, petsc (to use PETSc’s default)

• ftype - factor type, MAT_FACTOR_LU, MAT_FACTOR_CHOLESKY, MAT_FACTOR_ICC, MAT_FACTOR_ILU, MAT_FACTOR_QR

Output Parameter

• f - the factor matrix used with MatXXFactorSymbolic() calls

Options Database Key

• -mat_factor_bind_factorization <host, device> - Where to do matrix factorization? Default is device (might consume more device memory. One can choose host to save device memory). Currently only supported with MATSEQAIJCUSPARSE matrices.

Notes

Users usually access the factorization solvers via KSP

Some PETSc matrix formats have alternative solvers available that are contained in alternative packages such as pastix, superlu, mumps etc.

PETSc must have been ./configure to use the external solver, using the option –download-package

Some of the packages have options for controlling the factorization, these are in the form -prefix_mat_packagename_packageoption where prefix is normally obtained from the calling KSP/PC. If MatGetFactor() is called directly one can set call MatSetOptionsPrefixFactor() on the originating matrix or MatSetOptionsPrefix() on the resulting factor matrix.

Developer Note

This should actually be called MatCreateFactor() since it creates a new factor object

See Also

Matrices, Mat, Matrix Factorization, KSP, MatSolverType, MatFactorType, MatCopy(), MatDuplicate(), MatGetFactorAvailable(), MatFactorGetCanUseOrdering(), MatSolverTypeRegister(), MAT_FACTOR_LU, MAT_FACTOR_CHOLESKY, MAT_FACTOR_ICC, MAT_FACTOR_ILU, MAT_FACTOR_QR

Level

intermediate

Location

src/mat/interface/matrix.c

Examples

src/ksp/ksp/tutorials/ex52.c

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