Matrix: MathWorks/Sieber

Description: Default tol and symtol not sufficient. Jan Sieber, Univ Bristol

 (bipartite graph drawing) (graph drawing of A+A')

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• download as a MATLAB mat-file, file size: 100 KB. Use UFget(1378) or UFget('MathWorks/Sieber') in MATLAB.
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 Matrix properties number of rows 2,290 number of columns 2,290 nonzeros 14,873 structural full rank? yes structural rank 2,290 # of blocks from dmperm 1 # strongly connected comp. 1 explicit zero entries 0 nonzero pattern symmetry 73% numeric value symmetry 0% type real structure unsymmetric Cholesky candidate? no positive definite? no

 author Sieber editor T. Davis date 2006 kind counter-example problem 2D/3D problem? no

 Additional fields size and type b full 2290-by-1

 Ordering statistics: result nnz(chol(P*(A+A'+s*I)*P')) with AMD 16,008 Cholesky flop count 1.1e+05 nnz(L+U), no partial pivoting, with AMD 29,726 nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD 12,582 nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD 2,623,195

 SVD-based statistics: norm(A) 408380 min(svd(A)) 0.000885182 cond(A) 4.61351e+08 rank(A) 2,290 sprank(A)-rank(A) 0 null space dimension 0 full numerical rank? yes

 singular values (MAT file): click here SVD method used: s = svd (full (A)) ; 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.