Matrix properties
number of rows	11
number of columns	17
nonzeros	29
structural full rank?	yes
structural rank	11
# of blocks from dmperm	1
# strongly connected comp.	3
explicit zero entries	0
nonzero pattern symmetry	0%
numeric value symmetry	0%
type	real
structure	rectangular
Cholesky candidate?	no
positive definite?	no

author	J. Chinneck, E. Dravnieks
editor	J. Chinneck
date	1991
kind	linear programming problem
2D/3D problem?	no

Additional fields	size and type
b	full 11-by-1
c	full 17-by-1
lo	full 17-by-1
hi	full 17-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                                                         
-------------------                                                         
                                                                            
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.                                                                   
                                                                            

Ordering statistics:	result
nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD	30
nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD	32

SVD-based statistics:
norm(A)	3.35268
min(svd(A))	0.0223111
cond(A)	150.27
rank(A)	11
sprank(A)-rank(A)	0
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
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.