Re: [Help-glpk] Save solution in GLPK

[Cedric[FR]]

Hi,

In fact, I implement a column generation.

But, when I started again the GLPK simplex, the counter is incrementing.

But I want to initialize my solver by the precedent solution obtained

For example, I obtain:

      0:   objval =   0.000000000e+00   infeas =   1.000000000e+00 (0)
     15:   objval =   3.497400000e+04   infeas =   0.000000000e+00 (0)
*    15:   objval =   3.497400000e+04   infeas =   0.000000000e+00 (0)
*    29:   objval =   2.652371454e+02   infeas =   0.000000000e+00 (0)
OPTIMAL SOLUTION FOUND
     29:   objval =   0.000000000e+00   infeas =   1.000000000e+00 (0)
     44:   objval =   3.497400000e+04   infeas =   0.000000000e+00 (0)
*    44:   objval =   3.497400000e+04   infeas =   0.000000000e+00 (0)
*    58:   objval =   6.586143114e+01   infeas =   0.000000000e+00 (0)
OPTIMAL SOLUTION FOUND

At the second simplex, GLPK starts with an objval=0 instead of the precedent
solution.

Why?

did I use the routine lpx_warm_up?

thanks


Andrew Makhorin wrote:
> 
>> How can I save the precedent solution in GLPK?
> 
>> In fact, I add a new column at problem. And, I want to initialize my
>> solver by the precedent solution obtained.
> 
> Do nothing. The current basis (i.e. the set of row and column statuses)
> is always kept in the problem object.
> 
> However, if you then need to re-optimize your instance, make sure that
> before a call to lpx_simplex the lp presolver is disabled.
> 
> 
> 
> _______________________________________________
> Help-glpk mailing list
> address@hidden
> http://lists.gnu.org/mailman/listinfo/help-glpk
> 
> 

-- 
View this message in context: 
http://www.nabble.com/Save-solution-in-GLPK-tf3839145.html#a10965562
Sent from the Gnu - GLPK - Help mailing list archive at Nabble.com.