Matrix: LPnetlib/lp_wood1p

Description: Netlib LP problem wood1p: minimize c'*x, where Ax=b, lo<=x<=hi

LPnetlib/lp_wood1p graph
(bipartite graph drawing)


LPnetlib/lp_wood1p

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  • Matrix group: LPnetlib
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  • download as a MATLAB mat-file, file size: 175 KB. Use UFget(701) or UFget('LPnetlib/lp_wood1p') in MATLAB.
  • download in Matrix Market format, file size: 284 KB.
  • download in Rutherford/Boeing format, file size: 139 KB.

    Matrix properties
    number of rows244
    number of columns2,595
    nonzeros70,216
    structural full rank?yes
    structural rank244
    # of blocks from dmperm1
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetry 0%
    numeric value symmetry 0%
    typereal
    structurerectangular
    Cholesky candidate?no
    positive definite?no

    authorJ. Tomlin
    editorD. Gay
    date1989
    kindlinear programming problem
    2D/3D problem?no

    Additional fieldssize and type
    bfull 244-by-1
    cfull 2595-by-1
    lofull 2595-by-1
    hifull 2595-by-1
    z0full 1-by-1

    Notes:

    A Netlib LP problem, in lp/data.  For more information                    
    send email to netlib@ornl.gov with the message:                           
                                                                              
    	 send index from lp                                                      
    	 send readme from lp/data                                                
                                                                              
    The following are relevant excerpts from lp/data/readme (by David M. Gay):
                                                                              
    The column and nonzero counts in the PROBLEM SUMMARY TABLE below exclude  
    slack and surplus columns and the right-hand side vector, but include     
    the cost row.  We have omitted other free rows and all but the first      
    right-hand side vector, as noted below.  The byte count is for the        
    MPS compressed file; it includes a newline character at the end of each   
    line.  These files start with a blank initial line intended to prevent    
    mail programs from discarding any of the data.  The BR column indicates   
    whether a problem has bounds or ranges:  B stands for "has bounds", R     
    for "has ranges".                                                         
                                                                              
    The optimal value is from MINOS version 5.3 (of Sept. 1988)               
    running on a VAX with default options.                                    
                                                                              
                           PROBLEM SUMMARY TABLE                              
                                                                              
    Name       Rows   Cols   Nonzeros    Bytes  BR      Optimal Value         
    WOOD1P      245   2594    70216     328905        1.4429024116E+00        
                                                                              
    From John Tomlin.                                                         
    On the problems supplied by John Tomlin, MINOS 5.3 reports that about     
    10% to 57% of its steps are degenerate:                                   
         Name     Steps  Degen  Percent                                       
         WOOD1P    1059    471   44.48                                        
                                                                              
    Added to Netlib on  27 June 1989                                          
                                                                              
    

    Ordering statistics:result
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD248,714
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD19,080

    SVD-based statistics:
    norm(A)22731.2
    min(svd(A))1.71194e-10
    cond(A)1.3278e+14
    rank(A)243
    sprank(A)-rank(A)1
    null space dimension1
    full numerical rank?no
    singular value gap8.20792e+09

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

    LPnetlib/lp_wood1p 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.