LPnetlib/lpi_itest6
Netlib LP problem itest6: minimize c'*x, where Ax=b, lo<=x<=hi
Name 
lpi_itest6 
Group 
LPnetlib 
Matrix ID 
720 
Num Rows

11 
Num Cols

17 
Nonzeros

29 
Pattern Entries

29 
Kind

Linear Programming Problem 
Symmetric

No 
Date

1991 
Author

J. Chinneck, E. Dravnieks 
Editor

J. Chinneck 
Structural Rank 
11 
Structural Rank Full 
true 
Num Dmperm Blocks

1 
Strongly Connect Components

3 
Num Explicit Zeros

0 
Pattern Symmetry

0% 
Numeric Symmetry

0% 
Cholesky Candidate

no 
Positive Definite

no 
Type

real 
SVD Statistics 
Matrix Norm 
3.352685e+00 
Minimum Singular Value 
2.231112e02 
Condition Number 
1.502696e+02

Rank 
11 
sprank(A)rank(A) 
0 
Null Space Dimension 
0 
Full Numerical Rank? 
yes 
Download Singular Values 
MATLAB

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MATLAB
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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

ITEST6, ITEST2: very small problems having numerous clustered IISs.
These match problems 1 and 2, respectively, in Chinneck and Dravnieks
[1991]. Contributors: J.W. Chinneck and E.W. Dravnieks, Carleton
University.
Name Rows Cols Nonzeros Bounds Notes
itest6 12 8 23
REFERENCES

J.W. Chinneck and E.W. Dravnieks (1991). "Locating Minimal Infeasible
Constraint Sets in Linear Programs", ORSA Journal on Computing, Volume
3, No. 2.
