## BCSSTM02: BCS Structural Engineering Matrices (eigenvalue matrices)Oil rig -- statically condensed

### from set BCSSTRUC1, from the Harwell-Boeing Collection

From generalized eigenvalue problem Kx=(lambda)Mx. This is matrix M; matrix K is BCSSTK02 from BCSSTRUC1 set.
Result of applying static condensation to the oil rig model represented by BCSSTK04 and BCSSTM04. Static condensation can be applied in cases where the mass matrix is singular to reduce the problem order while preserving the spectrum. However, the reduced stiffness matrix is usually dense, which is the case here. Good sparse eigenvalue codes should be able to solve a large sparse problem much more quickly than a dense code can solve the reduced problem of order one-half or one-third the original. This problem is probably too small to demonstrate that effect.

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## Visualizations

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Structure Plot City Plot
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## Matrix Statistics

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Size Type
66 x 66, 66 entries real symmetric positive definite
Nonzeros
totaldiagonalbelow diagonalabove diagonalA-A'
66 66 0 0 0
Column Data Row Data
Average nonzeros per column : 1
Standard deviation : 0

index nonzeros 1 1 1 1

Average nonzeros per row : 1
Standard deviation : 0

index nonzeros 1 1 1 1

Bandwidths Profile Storage
 lower upper 1 1 0 0
minmaxave.std.dev.
lower bandwidth1 1 1 0
upper bandwidth1 1 1 0

Symmetric skyline storage requirement:66

Heaviest diagonals
 offset from main 0 66 100

Top 1 out of 1 nonvoid diagonals.
Conditioning
 Frobenius norm condition number (est.) 0.82 8.8 0.17 yes

## Set Information

Set BCSSTRUC1
Source: John Lewis, Boeing Computer Services, Seattle, Washington, USA
Discipline:Dynamic analyses in structural engineering
Accession:Summer 1982

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Last change in this page: Wed Sep 22 13:33:24 US/Eastern 2004 [Comments: ]