MatGetColoring

Gets a coloring for a matrix to reduce the number of function evaluations needed to compute a sparse Jacobian via differencing.

Synopsis

int MatGetColoring(Mat mat,MatColoringType type,ISColoring *iscoloring)

Collective on Mat

Input Parameters

mat -the matrix

type -type of coloring, one of the following:

     MATCOLORING_NATURAL - natural (one color for each column, very slow)

     MATCOLORING_SL - smallest-last

     MATCOLORING_LF - largest-first

     MATCOLORING_ID - incidence-degree

Output Parameters

iscoloring -the coloring

Options Database Keys

To specify the coloring through the options database, use one of the following

   -mat_coloring_type natural, -mat_coloring_type sl, -mat_coloring_type lf,

   -mat_coloring_type id

To see the coloring use

   -mat_coloring_view

Notes

These compute the graph coloring of the graph of A^{T}A. The coloring used for efficient (parallel or thread based) triangular solves etc is NOT yet available.

The user can define additional colorings; see MatColoringRegisterDynamic().

The sequential colorings SL, LF, and ID are obtained via the Minpack software that was converted to C using f2c.

Keywords

matrix, get, coloring