[Trilinos-Users] Using the EpetraExt_CrsGraph_MapColoring class

[Erik Boman]

Hi Erik,

I'm not sure about your specific question, but you should know that the
more recent work on coloring has been moved to the Zoltan and Isorropia
packages. Take a look at Isorropia::Epetra::Colorer at
http://trilinos.sandia.gov/packages/docs/r9.0/packages/isorropia/doc/html/classIsorropia_1_1Epetra_1_1Colorer.html

This package uses a more scalable parallel algorithm, so you may want to
try it. One drawback is that the current version is limited to
structurally symmetric matrices. We plan to support nonsymmetric
matrices in the next release.

Regards,
Erik 


On Mon, 2009-04-13 at 09:24 -0600, Bernsen, E. wrote:
> 
> Hello,
> 
> I'm trying to use the EpetraExt_CrsGraph_MapColoring class to color
> the independent columns of a graph and then use the
> FiniteDifferenceColoring class to construct a Jacobian matrix.
> Sometimes the coloring algorithms give unexpected results. For
> instance consider the attached program (test.C) which creates a 2x2
> triangular matrix and then colors the corresponding graph. I think the
> coloring of this matrix should result in two colors. However according
> to the output of the program (out.txt) only one color is required. The
> program was run on a single processor in this case.
> 
> When using the GREEDY algorithm instead of JONES_PLASSMEN the coloring
> seems to work allright as long as the program is run on a single
> processor. If more than one processor is used results seem to be also
> incorrect.
> 
> Is there a bug in the EpetraExt_CrsGraph_MapColoring class or is the
> use of this class in test.C incorrect?
> 
> Regards,
> 
> Erik Bernsen
> 
> 
> 
>