Matrix: Meszaros/iprob

Description: Problematic linear programming problem, Meszaros test set

 (undirected graph drawing)

• Matrix group: Meszaros
• download as a MATLAB mat-file, file size: 41 KB. Use UFget(1790) or UFget('Meszaros/iprob') in MATLAB.

 Matrix properties number of rows 3,001 number of columns 3,001 nonzeros 9,000 structural full rank? yes structural rank 3,001 # of blocks from dmperm 1 # strongly connected comp. 1 explicit zero entries 0 nonzero pattern symmetry symmetric numeric value symmetry 50% type real structure unsymmetric 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 3001-by-1 c full 3001-by-1 lo full 3001-by-1 hi full 3001-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(chol(P*(A+A'+s*I)*P')) with AMD 6,001 Cholesky flop count 1.2e+04 nnz(L+U), no partial pivoting, with AMD 9,001 nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD 6,001 nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD 4,504,501

 SVD-based statistics: norm(A) 132256 min(svd(A)) 3.1348e-17 cond(A) 4.21896e+21 rank(A) 3,000 sprank(A)-rank(A) 1 null space dimension 1 full numerical rank? no singular value gap 3.18999e+16

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