Description: Netlib LP problem scrs8: minimize c'*x, where Ax=b, lo<=x<=hi
|(bipartite graph drawing)|
|number of rows||490|
|number of columns||1,275|
|structural full rank?||yes|
|# of blocks from dmperm||26|
|# strongly connected comp.||1|
|explicit zero entries||0|
|nonzero pattern symmetry||0%|
|numeric value symmetry||0%|
|author||J. Ho, E. Loute|
|kind||linear programming problem|
|Additional fields||size and type|
A Netlib LP problem, in lp/data. For more information send email to email@example.com 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 SCRS8 491 1169 4029 36760 9.0429998619E+02 Supplied by Bob Fourer. When included in Netlib: Extra free rows omitted. Source: J.K. Ho and E. Loute, "A Set of Staircase Linear Programming Test Problems", Math. Prog. 20 (1981), pp. 245-250. 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) SCRS8 9.0429695380E+02 9.0429695380E+02
|nnz(V) for QR, upper bound nnz(L) for LU, with COLAMD||44,800|
|nnz(R) for QR, upper bound nnz(U) for LU, with COLAMD||7,494|
|null space dimension||0|
|full numerical rank?||yes|
|singular values (MAT file):||click here|
|SVD method used:||s = svd (full (A)) ;|
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.