Matrix: LPnetlib/lpi_box1
Description: Netlib LP problem box1: minimize c'*x, where Ax=b, lo<=x<=hi
|
| (bipartite graph drawing) |
 |
| Matrix properties | |
| number of rows | 231 |
| number of columns | 261 |
| nonzeros | 651 |
| structural full rank? | yes |
| structural rank | 231 |
| # of blocks from dmperm | 1 |
| # strongly connected comp. | 1 |
| explicit zero entries | 0 |
| nonzero pattern symmetry | 0% |
| numeric value symmetry | 0% |
| type | integer |
| structure | rectangular |
| Cholesky candidate? | no |
| positive definite? | no |
| author | Z. You |
| editor | J. Chinneck |
| date | 1992 |
| kind | linear programming problem |
| 2D/3D problem? | no |
| Additional fields | size and type |
| b | full 231-by-1 |
| c | full 261-by-1 |
| lo | full 261-by-1 |
| hi | full 261-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):
In the following, IIS stands for Irreducible Infeasible Subsystem, a set
of constraints which is itself infeasible, but becomes feasible when any
one member is removed. Isolating an IIS from within the larger set of
constraints defining the model is one analysis approach.
PROBLEM DESCRIPTION
-------------------
BOX1, EX72A, EX73A: medium problems derived from research on using the
infeasibility version of viability analysis [Chinneck 1992] to analyze
petri net models. All three problems are volatile, showing IISs of
widely differing size depending on the algorithm applied. Contributor:
Zhengping You, Carleton University.
Name Rows Cols Nonzeros Bounds Notes
box1 232 261 912 B all cols are LO bounded
REFERENCES
----------
J.W. Chinneck (1992). "Viability Analysis: A Formulation Aid for All
Classes of Network Models", Naval Research Logistics, Vol. 39, pp.
531-543.
Added to Netlib on Sept. 19, 1993
| Ordering statistics: | result |
| nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD | 854 |
| nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD | 1,164 |
| SVD-based statistics: | |
| norm(A) | 6.01299 |
| min(svd(A)) | 2.09309e-16 |
| cond(A) | 2.87278e+16 |
| rank(A) | 214 |
| sprank(A)-rank(A) | 17 |
| null space dimension | 17 |
| full numerical rank? | no |
| singular value gap | 9.98733e+13 |
| 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.