Matrix: Meszaros/dbir2

Description: linear programming problem, C. Meszaros test set

 (bipartite graph drawing)

• Matrix group: Meszaros
• download as a MATLAB mat-file, file size: 2 MB. Use UFget(1706) or UFget('Meszaros/dbir2') in MATLAB.

 Matrix properties number of rows 18,906 number of columns 45,877 nonzeros 1,158,159 structural full rank? no structural rank 18,904 # of blocks from dmperm 29 # strongly connected comp. 2,366 explicit zero entries 0 nonzero pattern symmetry 0% numeric value symmetry 0% type integer structure rectangular Cholesky candidate? no positive definite? no

 author editor C. Meszaros date 2004 kind linear programming problem 2D/3D problem? no

 Additional fields size and type b full 18906-by-1 c full 45877-by-1 lo full 45877-by-1 hi full 45877-by-1 z0 full 1-by-1

Notes:

http://www.sztaki.hu/~meszaros/public_ftp/lptestset
Converted to standard form via Resende and Veiga's mpsrd:
minimize c'*x, subject to A*x=b and lo <= x <= hi

 Ordering statistics: result nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD 41,117,320 nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD 3,005,677

 SVD-based statistics: norm(A) 2.56248e+06 min(svd(A)) 0 cond(A) Inf rank(A) 18,904 sprank(A)-rank(A) 0 null space dimension 2 full numerical rank? no singular value gap Inf

 singular values (MAT file): click here SVD method used: s = svd (full (R)) ; where [~,R,E] = spqr (A') with droptol of zero status: SVD did not converge.