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NOS6: Lanczos with partial reorthogonalization
Finite difference approximation to Poisson's equation in an L-shaped region, mixed boundary conditions.

from set LANPRO, from the Harwell-Boeing Collection

[Download] [Visualizations] [Matrix Statistics] [Set Information]


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Visualizations

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Structure Plot City Plot
structure plot city plot
3D Interactive City Plot

[ VRML Version 2, gzipped ] 461836 bytes


Matrix Statistics

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Size Type
675 x 675, 1965 entries real symmetric positive definite
Nonzeros
totaldiagonalbelow diagonalabove diagonalA-A'
3255 675 1290 1290 0
Column Data Row Data
Average nonzeros per column : 4.8
Standard deviation : 0.4

indexnonzeros
longest32 5
shortest1 3

Average nonzeros per row : 4.8
Standard deviation : 0.4

indexnonzeros
longest32 5
shortest1 3

Bandwidths Profile Storage
lower31 upper31
average |i-j|10 std.dev.13
minmaxave.std.dev.
lower bandwidth1 31 25 8.5
upper bandwidth1 31 25 8.5

Symmetric skyline storage requirement:16904

Heaviest diagonals
offset from main0 -1 1 -30 30 -15 15
nonzeros675 645 645 435 435 210 210
accumulated percent20.7440.5560.3773.7387.1093.55100.00

Top 7 out of 7 nonvoid diagonals.
Conditioning
Frobenius norm4.5e+07 condition number (est.)8e+06
2-norm (est.)7.7e+06 diagonal dominanceyes


Set Information

Set LANPRO
Source: Horst Simon, Boeing Computer Services, Seattle, Washington.
Discipline:Linear equations in structural engineering
Accession:Spring 1982


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