Matrix: Mittelmann/rail2586

Description: Italian railways (H. Mittelmann test set)

 (bipartite graph drawing)

• Matrix group: Mittelmann
• download as a MATLAB mat-file, file size: 6 MB. Use UFget(1657) or UFget('Mittelmann/rail2586') in MATLAB.

 Matrix properties number of rows 2,586 number of columns 923,269 nonzeros 8,011,362 structural full rank? yes structural rank 2,586 # of blocks from dmperm 1 # strongly connected comp. 8 explicit zero entries 0 nonzero pattern symmetry 0% numeric value symmetry 0% type integer structure rectangular Cholesky candidate? no positive definite? no

 author P. Nobili editor J. Beasley date 2005 kind linear programming problem 2D/3D problem? no

 Additional fields size and type b full 2586-by-1 c full 923269-by-1 lo full 923269-by-1 hi full 923269-by-1 z0 full 1-by-1

Notes:

```Hans Mittelmann test set, http://plato.asu.edu/ftp/lptestset
minimize c'*x, subject to A*x=b and lo <= x <= hi

RAIL: set covering problems from the Italian railroad, see
http://people.brunel.ac.uk/~mastjjb/jeb/orlib/scpinfo.html
```

 Ordering statistics: result nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD 1,052,862,453 nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD 1,522,581

 SVD-based statistics: norm(A) 496.004 min(svd(A)) 1 cond(A) 496.004 rank(A) 2,586 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 (R)) ; where [~,R,E] = spqr (A') with droptol of zero status: ok