Posted by Dan on November 21, 1997 at 21:41:56:

In Reply to: sparse matrix posted by Christof on October 30, 1997 at 06:19:56:

:

: Hi everybody,

: I"m looking for examples of systems of equations with large unstructured sparse systemmatrix (>1.000.000 unknowns) which are symmetric positiv definite and have any practical relevance.

: Could anybody help me with yhat ?

: Thanx

: Chris .

Hi Chris,

The linear structural analysis of a building or structure with a lot of members will give you what you want.... a positive definite symmetric matrix which is sparse. I have a program which will create such a matrix but... it is currently limited to about 33000 unknowns. There are commercial programs out there which can give you what you want. Just be sure to run them and turn off bandwidth reduction features in the program if you want coeffecients spread throughout your matrices.

Dan :-)