Description: Netlib LP problem woodinfe: minimize c'*x, where Ax=b, lo<=x<=hi
|(bipartite graph drawing)|
|number of rows||35|
|number of columns||89|
|structural full rank?||yes|
|# of blocks from dmperm||3|
|# strongly connected comp.||6|
|explicit zero entries||0|
|nonzero pattern symmetry||0%|
|numeric value symmetry||0%|
|kind||linear programming problem|
|Additional fields||size and type|
An infeasible Netlib LP problem, in lp/infeas. For more information send email to firstname.lastname@example.org 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 ------------------- FOREST6, WOODINFE: very small problems derived from network-based forestry models. The IIS in FOREST6 includes most of the rows. WOODINFE is the example problem discussed in detail in Greenberg , and has a very small IIS. Contributor: H.J. Greenberg, University of Colorado at Denver. Name Rows Cols Nonzeros Bounds Notes woodinfe 36 89 209 B REFERENCES ---------- H.J. Greenberg (1993). "A Computer-Assisted Analysis System for Mathematical Programming Models and Solutions: A User's Guide for ANALYZE", Kluwer Academic Publishers, Boston.
|nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD||284|
|nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD||102|
|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|
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.