[Cbc] Reporting progress

[Christian Schmidt]

Hi,

how can we report the progress of solving in Cbc?

1) For MIP I've registered an CbcEventHandler and calculate the gap from

double ub = getModel()->getObjValue()
double lb = getModel()->getBestPossibleObjValue()
double gap = fabs(ub - lb) / (lb != 0 ? fabs(lb) : fabs(ub))

I could use 1 - min(gap, 1) as a progress measure. But typically the gap decreases exponentially or polynomially, so e.g.

progress = 1 - pow(gap, 1.0 / 3)

seems to be more "smooth". Are there any other ideas?

2) What would I do for big LPs? The CbcEventHandler will not be called... Any ideas here?


Best regards,

Christian
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