BLCKHOLE is an artificial finite-element model consisting of a finely gridded geodesic dome clamped to a coarsely gridded rectangular base. Because of the difference in gridding factors, the interface nodes on the base have a very high order. SSTMODEL is the elemental connectivity for the stiffness matrix of a 1960's design for a supersonic transport (the Boeing 2707).

For the BLCKHOLE example, the strange gridding plays havoc with orderings based on level structures, and is nearly a worst case for the Gibbs-Poole-Stockmeyer heuristic. Reverse Cuthill-McKee and Gibbs-Poole- Stockmeyer are nearly a factor of two away from obtaining the minimum bandwidth of this problem. General sparse methods fair well despite the strange gridding.

Matrices in this set:

BLCKHOLE (pattern symmetric indefinite, 2132 by 2132, 8502 entries), Geodesic dome clamped to rectangular base

SSTMODEL (pattern symmetric indefinite, 3345 by 3345, 13047 entries), Elemental connectivity for the stiffness matrix of a 1960's design for a supersonic transport (Boeing 2707)