Matrix: TKK/tube2

Description: Tube problem from R. Kouhia

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• download as a MATLAB mat-file, file size: 251 KB. Use UFget(1915) or UFget('TKK/tube2') in MATLAB.
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 Matrix properties number of rows 21,498 number of columns 21,498 nonzeros 897,056 structural full rank? yes structural rank 21,498 # of blocks from dmperm 1 # strongly connected comp. 1 explicit zero entries 0 nonzero pattern symmetry symmetric numeric value symmetry symmetric type integer structure symmetric Cholesky candidate? yes positive definite? no

 author R. Kouhia editor T. Davis date 2008 kind structural problem 2D/3D problem? yes

 Additional fields size and type b full 21498-by-1

Notes:

```Matrix problems from Reijo Kouhia, Structural Mechanics, Helsinki
University of Technology.   http://users.tkk.fi/~kouhia/sparse.html
```

 Ordering statistics: result nnz(chol(P*(A+A'+s*I)*P')) with AMD 2,251,690 Cholesky flop count 4.6e+08 nnz(L+U), no partial pivoting, with AMD 4,481,882 nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD 6,715,664 nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD 12,198,788

 SVD-based statistics: norm(A) 173.029 min(svd(A)) 4.05471e-202 cond(A) 4.26735e+203 rank(A) 3,583 sprank(A)-rank(A) 17,915 null space dimension 17,915 full numerical rank? no singular value gap 8.4176e+09

 singular values (MAT file): click here SVD method used: s = svd (full (R)) ; where [~,R,E] = spqr (A) with droptol of zero status: ok

For a description of the statistics displayed above, click here.

Maintained by Tim Davis, last updated 12-Mar-2014.
Matrix pictures by cspy, a MATLAB function in the CSparse package.
Matrix graphs by Yifan Hu, AT&T Labs Visualization Group.