Could be just a high "Condition Number" that's associated with his matrix.

http://en.wikipedia.org/wiki/Matrix_condition_number

Dana DeLouis


Gary''s Student wrote:
No guarantee at all!

Clearly David is having problems with some of his matrices. The code in
wikipedia is small enough that it could be re-coded in a couple of hours.

David could compare the results from the Gaussian method to whatever
Microsoft uses.