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


PetscErrorCode PETSCMAT_DLLEXPORT MatGetColoring(Mat mat,const 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


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.


matrix, get, coloring

See Also

MatGetColoringTypeFromOptions(), MatColoringRegisterDynamic(), MatFDColoringCreate(),

Index of all MatOrderings routines
Table of Contents for all manual pages
Index of all manual pages