[Help-glpk] time - glpk test

[Pradeep]

Hi all,
I have two sets of problems with following
characteristics
Set 1:
number of variables: n
number of constraints: 6*sqrt(n)-2 (always n is
perfect sq)
Set 2:
number of variables: n
number of constraints: n

all variables are binary (0 or 1)

I modelled these two problem sets in glpk and here is
the results
Set 1:
number of variables: 900
number of constraints: 178
takes about 5 mins on a P4 128MB ram running Linux and
Gnome etc..
Set 2:
number of variables: 518
number of constraints: 518
ILP takes too long time (i waied for more than 1.5 hrs
and still could not get an optimal)

Is there any problem here ?. I could not get why the
Set 2 takes this long despite lesser number of
variables.

In both cases relaxed simplex works equally fast.

Thanks
Pradeep


        
        
                
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