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

from set BCSSTRUC6, from the Harwell-Boeing Collection

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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.

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Structure Plot
structure plot

Matrix Statistics

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Size Type
2132 x 2132, 8502 entries pattern symmetric indefinite
totaldiagonalbelow diagonalabove diagonalA-A'
14872 2132 6370 6370 0
Column Data Row Data
Average nonzeros per column : 7
Standard deviation : 0.95

longest2073 20
shortest2074 1

Average nonzeros per row : 7
Standard deviation : 0.95

longest2073 20
shortest2074 1

Bandwidths Profile Storage
lower1806 upper1806
average |i-j|55
lower bandwidth1 1806 89 2.1e+02
upper bandwidth1 1806 89 2.1e+02

Symmetric skyline storage requirement:190620

Heaviest diagonals
offset from main0 -1 1 -18 18 -17 17 -16 16 -15
nonzeros2132 1917 1917 350 350 330 330 310 310 290
accumulated percent14.3427.2340.1242.4744.8247.0449.2651.3453.4355.38

Top 10 out of 699 nonvoid diagonals.
Pattern matrix. No conditioning information.

Set Information

Source: Ed Meyer, Boeing Computer Services
Discipline:Structural engineering
Accession:Summer 1983

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