Matrix: LPnetlib/lp_sierra

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

LPnetlib/lp_sierra graph
(bipartite graph drawing)


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  • Matrix group: LPnetlib
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  • download as a MATLAB mat-file, file size: 19 KB. Use UFget(690) or UFget('LPnetlib/lp_sierra') in MATLAB.
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  • download in Rutherford/Boeing format, file size: 22 KB.

    Matrix properties
    number of rows1,227
    number of columns2,735
    structural full rank?yes
    structural rank1,227
    # of blocks from dmperm1
    # strongly connected comp.1
    explicit zero entries0
    nonzero pattern symmetry 0%
    numeric value symmetry 0%
    Cholesky candidate?no
    positive definite?no

    authorR. Helgason, J. Kennington, P. Wong
    editorR. Fourer
    kindlinear programming problem
    2D/3D problem?no

    Additional fieldssize and type
    bfull 1227-by-1
    cfull 2735-by-1
    lofull 2735-by-1
    hifull 2735-by-1
    z0full 1-by-1


    A Netlib LP problem, in lp/data.  For more information                    
    send email to 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 BOUND-TYPE TABLE below shows the bound types       
    present in those problems that have bounds.                               
    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         
    SIERRA     1228   2036     9252      76627  B     1.5394362184E+07        
            BOUND-TYPE TABLE                                                  
    SIERRA     UP                                                             
    Supplied by Bob Fourer.                                                   
    When included in Netlib: Explicit zeros omitted.                          
    Bob Bixby reports that the CPLEX solver (running on a Sparc station)      
    finds slightly different optimal values for some of the problems.         
    On a MIPS processor, MINOS version 5.3 (with crash and scaling of         
    December 1989) also finds different optimal values for some of the        
    problems.  The following table shows the values that differ from those    
    shown above.  (Whether CPLEX finds different values on the recently       
    added problems remains to be seen.)                                       
    Problem        CPLEX(Sparc)          MINOS(MIPS)                          
    SIERRA                            1.5394364186E+07                        
    Source: GFRD-PNC, SIERRA: R. Helgason, J. Kennington, and P. Wong,        
    "An Application of Network Programming for National Forest Planning",     
    Technical Report OR 81006, Dept. of Operations Research, Southern         
    Methodist University.                                                     

    Ordering statistics:result
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD121,258
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD12,744

    SVD-based statistics:
    null space dimension10
    full numerical rank?no
    singular value gap7.29823e+09

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

    LPnetlib/lp_sierra 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.