Matrix: LPnetlib/lpi_pilot4i

Description: Netlib LP problem pilot4i: minimize c'*x, where Ax=b, lo<=x<=hi

LPnetlib/lpi_pilot4i graph
(bipartite graph drawing)

LPnetlib/lpi_pilot4i dmperm of LPnetlib/lpi_pilot4i

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  • Matrix group: LPnetlib
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  • download as a MATLAB mat-file, file size: 36 KB. Use UFget(726) or UFget('LPnetlib/lpi_pilot4i') in MATLAB.
  • download in Matrix Market format, file size: 29 KB.
  • download in Rutherford/Boeing format, file size: 22 KB.

    Matrix properties
    number of rows410
    number of columns1,123
    structural full rank?yes
    structural rank410
    # of blocks from dmperm9
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetry 0%
    numeric value symmetry 0%
    Cholesky candidate?no
    positive definite?no

    authorJ. Stone
    editorJ. Chinneck
    kindlinear programming problem
    2D/3D problem?no

    Additional fieldssize and type
    bfull 410-by-1
    cfull 1123-by-1
    lofull 1123-by-1
    hifull 1123-by-1
    z0full 1-by-1


    An infeasible Netlib LP problem, in lp/infeas.  For more information        
    send email to with the message:                             
    	send index from lp                                                         
    	send readme from lp/data                                                   
    	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                                                         
    PILOT4I:  medium size problem generated by doctoring the original NETLIB    
    PILOT4 model.  Contributor:  John Stone, Ketron Management Science.         
    Name       Rows   Cols   Nonzeros Bounds      Notes                         
    pilot4i     411   1000     5145   B FR FX                                   
    Added to Netlib on Sept. 19, 1993                                           

    Ordering statistics:result
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD88,693
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD14,742

    SVD-based statistics:
    null space dimension0
    full numerical rank?yes

    singular values (MAT file):click here
    SVD method used:s = svd (full (A)) ;

    LPnetlib/lpi_pilot4i svd

    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.