I'm dealing with a MIP and I was wondering if OPL offers a way to know, at the end of the computation, what was the value of the LP relaxation at root node.
I mean, I can surely look at the log, but I was looking for a way to retrieve it programmatically.
I have already tried to apply an approach made up of:
- calling convertAllIntVars()
- calling solve()
- calling getObjValue()
- calling unconvertAllIntVars()
- calling solve() again
and clearly it works; but the second call to solve() restarts the solving procedure from scratch - at least it seems so, since in the log of the second call to solve() you clearly find the "Root relaxation solution time" message.
The problem is that I would like to impose an overall time limit T. Suppose T = 3600s, and also that root LP relaxation solution takes an important share -say, the half- of such a time limit. If I follow the aforementioned approach and impose the 3600s limit on both the call to solve(), it is going to take me one and a half times T to get all the informations I'm looking for, whereas if there was a way to access time and value of LP relaxation of the root node after the MIP computation ends, it would cost only the time T of one run.
Does anyone know if there's a way to retrieve such informations in OPL?
Thank you in advance for your help,