Originally posted by: rocarvaj

Hello!

According to the CPLEX documentation, one can use informational callbacks in the distributed MIP optimizer. But during the ramp up phase certain information is not available, for example B&B node count and CPXgetcallbackinfo will return 0 when a CPX_CALLBACK_INFO_NODE_COUNT query is made.

My question is: Is there a way of finding out whether CPLEX is done with ramp up and started branching? I thought that maybe there was a special wherefrom value when the informational callback function is called, but I can't find one.

Thanks in advance!

Rodolfo

There is no special wherefrom parameter to indicate that. But the B&B node count should be >0 when the callback is invoked during distributed B&B. Do you observe otherwise? The node count is 0 during all of rampup since rampup itself is not considered distributed B&B.