Description: Netlib LP problem afiro: minimize c'*x, where Ax=b, lo<=x<=hi
|(bipartite graph drawing)|
|number of rows||27|
|number of columns||51|
|structural full rank?||yes|
|# of blocks from dmperm||1|
|# strongly connected comp.||1|
|explicit zero entries||0|
|nonzero pattern symmetry||0%|
|numeric value symmetry||0%|
|kind||linear programming problem|
|Additional fields||size and type|
A Netlib LP problem, in lp/data. For more information send email to firstname.lastname@example.org 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 AFIRO 28 32 88 794 -4.6475314286E+02 From Michael Saunders, Systems Optimization Laboratory at Stanford University. 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 ---- -------- ---- ---- ----- ----------------- ---- ---- ---- ---- 1. AFIRO 28 32 88 -4.6475314E+02 6 0.5 6 0.5 * 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).
|nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD||262|
|nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD||110|
|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|
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.