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ngraph.sparse-collection

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Subset of the University of Florida sparse matrix collection

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# LPnetlib/lpi_cplex1 UF Sparse Matrix Collection, Tim Davis http://www.cise.ufl.edu/research/sparse/matrices/LPnetlib/lpi_cplex1 [Netlib LP problem cplex1: minimize c'*x, where Ax=b, lo<=x<=hi] id: 710 date: 1993 author: E. Klotz ed: J. Chinneck fields: title name A b id aux kind date author ed notes aux: c lo hi z0 kind: linear programming problem 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 ------------------- CPLEX1, CPLEX2: medium and large problems respectively. CPLEX1 referred to as CPLEX problem in Chinneck [1993], and is remarkably non-volatile, showing a single small IIS regardless of the IIS algorithm applied. CPLEX2 is an almost-feasible problem. Contributor: Ed Klotz, CPLEX Optimization Inc. Name Rows Cols Nonzeros Bounds Notes cplex1 3006 3221 10664 B dense col (> 1500) REFERENCES ---------- J.W. Chinneck (1993). "Finding the Most Useful Subset of Constraints for Analysis in an Infeasible Linear Program", technical report SCE-93-07, Systems and Computer Engineering, Carleton University, Ottawa, Canada. ![LPnetlib/lpi_cplex1](http://yifanhu.net/GALLERY/GRAPHS/GIF_SMALL/LPnetlib@lpi_cplex1.gif)