BLCKHOLE: BCS Structural Engineering Matrices (linear equations)
Geodesic dome clamped to rectangular base

from set BCSSTRUC6, from the Harwell-Boeing Collection

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. 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.

Download as

Compressed MatrixMarket format file: blckhole.mtx.gz (17771 bytes)
Compressed Harwell-Boeing format file: blckhole.psa.gz (16126 bytes)

Visualizations

Click on image to get an enlarged version. Click on label to get an explanation.

Structure Plot

Matrix Statistics

Size	Type
2132 x 2132, 8502 entries	pattern symmetric indefinite
Nonzeros
total diagonal below diagonal above diagonal A-A' 14872 2132 6370 6370 0
Column Data	Row Data
Average nonzeros per column : 7 Standard deviation : 0.95 index nonzeros longest 2073 20 shortest 2074 1	Average nonzeros per row : 7 Standard deviation : 0.95 index nonzeros longest 2073 20 shortest 2074 1
Bandwidths	Profile Storage
lower 1806 upper 1806 average |i-j| 55 std.dev. 1.7e+02	min max ave. std.dev. lower bandwidth 1 1806 89 2.1e+02 upper bandwidth 1 1806 89 2.1e+02 Symmetric skyline storage requirement:190620
Heaviest diagonals
offset from main 0 -1 1 -18 18 -17 17 -16 16 -15 nonzeros 2132 1917 1917 350 350 330 330 310 310 290 accumulated percent 14.34 27.23 40.12 42.47 44.82 47.04 49.26 51.34 53.43 55.38 Top 10 out of 699 nonvoid diagonals.
Conditioning
Pattern matrix. No conditioning information.

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Last change in this page: Wed Sep 22 13:33:28 US/Eastern 2004 [Comments: ]