Matrix: LPnetlib/lp_share2b

Description: Netlib LP problem share2b: minimize c'*x, where Ax=b, lo<=x<=hi

LPnetlib/lp_share2b graph
(bipartite graph drawing)


  • Home page of the UF Sparse Matrix Collection
  • Matrix group: LPnetlib
  • Click here for a description of the LPnetlib group.
  • Click here for a list of all matrices
  • Click here for a list of all matrix groups
  • download as a MATLAB mat-file, file size: 5 KB. Use UFget(682) or UFget('LPnetlib/lp_share2b') in MATLAB.
  • download in Matrix Market format, file size: 5 KB.
  • download in Rutherford/Boeing format, file size: 4 KB.

    Matrix properties
    number of rows96
    number of columns162
    structural full rank?yes
    structural rank96
    # 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

    authorM. Saunders
    editorD. Gay
    kindlinear programming problem
    2D/3D problem?no

    Additional fieldssize and type
    bfull 96-by-1
    cfull 162-by-1
    lofull 162-by-1
    hifull 162-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                                                    
    	 send minos 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             
    SHARE2B      97     79      730       4795       -4.1573224074E+02            
    From Michael Saunders, Systems Optimization Laboratory at Stanford University.
    When included in Netlib: Extra free rows omitted.                             
    The following are relevant excerts from lp/data/minos (by Michael Saunders),  
    regarding experience with MINOS 5.0 on the problems he provided:              
                                                         (unscaled)   (scaled)    
    File   Name    Rows  Cols  Elems  Optimal Objective  Itns  Time  Itns  Time   
    ---- --------  ----  ----  -----  -----------------  ----  ----  ----  ----   
      3. SHARE2B     99    79    802 -4.1573224E+02        91   1.3   121   1.4   
    * Objective  is the first row of type N.  It is minimized except as shown.    
    * Itns       is the number of iterations required to solve the problem        
                 by the primal simplex method, as implemented in the Fortran      
                 code MINOS 5.0 (May 1985), using default values for all          
                 parameters.  (The initial basis is triangular.)                  
    * Time       is the processor time required on an IBM 3081K.  The MINOS       
                 source code was compiled with the IBM Fortran 77 compiler        
                 VS FORTRAN, using the options NOSDUMP, NOSYM and OPT(3).         

    Ordering statistics:result
    nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD2,659
    nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD1,052

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

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

    LPnetlib/lp_share2b 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.