Matrix: LPnetlib/lpi_gran
Description: Netlib LP problem gran: minimize c'*x, where Ax=b, lo<=x<=hi
|
| (bipartite graph drawing) |
 |
 |
 |
| Matrix properties | |
| number of rows | 2,658 |
| number of columns | 2,525 |
| nonzeros | 20,111 |
| structural full rank? | no |
| structural rank | 2,311 |
| # of blocks from dmperm | 1,267 |
| # strongly connected comp. | 1,243 |
| explicit zero entries | 0 |
| nonzero pattern symmetry | 0% |
| numeric value symmetry | 0% |
| type | real |
| structure | rectangular |
| Cholesky candidate? | no |
| positive definite? | no |
| author | R. Main |
| editor | J. Chinneck |
| date | 1993 |
| kind | linear programming problem |
| 2D/3D problem? | no |
| Additional fields | size and type |
| b | full 2658-by-1 |
| c | full 2525-by-1 |
| lo | full 2525-by-1 |
| hi | full 2525-by-1 |
| z0 | full 1-by-1 |
Notes:
An infeasible Netlib LP problem, in lp/infeas. For more information
send email to netlib@ornl.gov with the message:
send index from lp
send readme from lp/infeas
The lp/infeas directory contains infeasible linear programming test problems
collected by John W. Chinneck, Carleton Univ, Ontario Canada. The following
are relevant excerpts from lp/infeas/readme (by John W. Chinneck):
PROBLEM DESCRIPTION
-------------------
GOSH, GRAN, PANG: these very large, large, and medium size models,
respectively, problems arose from British Petroleum operations models.
Contributor: Roger Main, BP Oil.
Name Rows Cols Nonzeros Bounds Notes
gran 2569 2520 20151 B FX
Added to Netlib on Sept. 19, 1993
| Ordering statistics: | result |
| nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 206,097 |
| nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 190,918 |
| SVD-based statistics: | |
| norm(A) | 2079.02 |
| min(svd(A)) | 1.79119e-17 |
| cond(A) | 1.16069e+20 |
| rank(A) | 1,938 |
| sprank(A)-rank(A) | 373 |
| null space dimension | 587 |
| full numerical rank? | no |
| singular value gap | 131.675 |
| 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.