[Help-glpk] how to use warmup

[nicolas.derhy]

Hello,

I want to make some successive lp optimizations where only second member of 
some constraints change.
So my idea was to solve the first lp problem, to save the basis corresponding 
to the optimal solution and then to use this basis when solving the others 
problem (in order to greatly speed up the optimization process).

I did not find which method used for reading/writing .bas file so I tried 
calling only warmup method between two optimizations. It seems to have no 
effect because the output always specify that it constructs initial basis even 
when using warmup.
Finally I switched off presolve and it worked ! 

So my question is : is it possible to use presolve (which is great to decrease 
the size of lp problems) AND warmup ? Besides, in the java implementation of 
glpk, I found readBas and writeBas method, is there an equivalent in the native 
glpk API ?

Best regards.

Nicolas 




GDF SUEZ Mail Disclaimer: http://www.gdfsuez.com/disclaimer/disclaimer-fr.html