scipy.sparse.linalg.splu¶

scipy.sparse.linalg.splu(A, permc_spec=None, diag_pivot_thresh=None, drop_tol=None, relax=None, panel_size=None, options={})[source]¶

Compute the LU decomposition of a sparse, square matrix.

Parameters:

Parameters:	A : sparse matrix Sparse matrix to factorize. Should be in CSR or CSC format. permc_spec : str, optional How to permute the columns of the matrix for sparsity preservation. (default: ‘COLAMD’) `NATURAL`: natural ordering. `MMD_ATA`: minimum degree ordering on the structure of A^T A. `MMD_AT_PLUS_A`: minimum degree ordering on the structure of A^T+A. `COLAMD`: approximate minimum degree column ordering diag_pivot_thresh : float, optional Threshold used for a diagonal entry to be an acceptable pivot. See SuperLU user’s guide for details [R307] drop_tol : float, optional (deprecated) No effect. relax : int, optional Expert option for customizing the degree of relaxing supernodes. See SuperLU user’s guide for details [R307] panel_size : int, optional Expert option for customizing the panel size. See SuperLU user’s guide for details [R307] options : dict, optional Dictionary containing additional expert options to SuperLU. See SuperLU user guide [R307] (section 2.4 on the ‘Options’ argument) for more details. For example, you can specify `options=dict(Equil=False, IterRefine='SINGLE'))` to turn equilibration off and perform a single iterative refinement.
Returns:	invA : scipy.sparse.linalg.SuperLU Object, which has a `solve` method.

A : sparse matrix

Sparse matrix to factorize. Should be in CSR or CSC format.

permc_spec : str, optional

How to permute the columns of the matrix for sparsity preservation. (default: ‘COLAMD’)

NATURAL: natural ordering.

MMD_ATA: minimum degree ordering on the structure of A^T A.

MMD_AT_PLUS_A: minimum degree ordering on the structure of A^T+A.

COLAMD: approximate minimum degree column ordering

diag_pivot_thresh : float, optional

Threshold used for a diagonal entry to be an acceptable pivot. See SuperLU user’s guide for details [R307]

drop_tol : float, optional

(deprecated) No effect.

relax : int, optional

Expert option for customizing the degree of relaxing supernodes. See SuperLU user’s guide for details [R307]

panel_size : int, optional

Expert option for customizing the panel size. See SuperLU user’s guide for details [R307]

options : dict, optional

Dictionary containing additional expert options to SuperLU. See SuperLU user guide [R307] (section 2.4 on the ‘Options’ argument) for more details. For example, you can specify options=dict(Equil=False, IterRefine='SINGLE')) to turn equilibration off and perform a single iterative refinement.

Returns:

invA : scipy.sparse.linalg.SuperLU

Object, which has a solve method.