Re: [Help-glpk] lp/mip problem data in dimacs-like format

[Andrew Makhorin]

> Would it be possible to have a simple example on this new dimacs like
> data format? I presumed that this new format only applies to GLPK, not
> on MathProg. An example will be easy to visualise the new data format,
> in my case.

This is an example model in cplex lp format:

\* Problem: transp *\

Minimize
 cost: + 0.225 x(Seattle,New~York) + 0.153 x(Seattle,Chicago)
 + 0.162 x(Seattle,Topeka) + 0.225 x(San~Diego,New~York)
 + 0.162 x(San~Diego,Chicago) + 0.126 x(San~Diego,Topeka)

Subject To
 supply(Seattle): + x(Seattle,New~York) + x(Seattle,Chicago)
 + x(Seattle,Topeka) <= 350
 supply(San~Diego): + x(San~Diego,New~York) + x(San~Diego,Chicago)
 + x(San~Diego,Topeka) <= 600
 demand(New~York): + x(Seattle,New~York) + x(San~Diego,New~York) >= 325
 demand(Chicago): + x(Seattle,Chicago) + x(San~Diego,Chicago) >= 300
 demand(Topeka): + x(Seattle,Topeka) + x(San~Diego,Topeka) >= 275

End

The same model in glpk lp/mip (dimacs-like) format looks like the
following (please note that this is a preliminary version):

n transp
p lp 6 6 18
z cost
r 1 cost
i 1 f
r 2 supply[Seattle]
i 2 u 350
r 3 supply[San-Diego]
i 3 u 600
r 4 demand[New-York]
i 4 l 325
r 5 demand[Chicago]
i 5 l 300
r 6 demand[Topeka]
i 6 l 275
x 1 x[Seattle,New-York]
j 1 l 0
a 0 1 0.225
x 2 x[Seattle,Chicago]
j 2 l 0
a 0 2 0.153
x 3 x[Seattle,Topeka]
j 3 l 0
a 0 3 0.162
x 4 x[San-Diego,New-York]
j 4 l 0
a 0 4 0.225
x 5 x[San-Diego,Chicago]
j 5 l 0
a 0 5 0.162
x 6 x[San-Diego,Topeka]
j 6 l 0
a 0 6 0.126
a 1 1 0.225
a 1 2 0.153
a 1 3 0.162
a 1 4 0.225
a 1 5 0.162
a 1 6 0.126
a 2 1 1
a 2 2 1
a 2 3 1
a 3 4 1
a 3 5 1
a 3 6 1
a 4 1 1
a 4 4 1
a 5 2 1
a 5 5 1
a 6 3 1
a 6 6 1
c eof