# Philip Taffet

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## Activity overview

Latest activity by Philip Taffet
• Philip Taffet commented,

Here's an idea for a workaround: I'm assuming your problem is min(obj) where obj is a variable. You can use a combination of big-M constraints and no-good cuts to form a user cutting plane. Sup...

• Philip Taffet commented,

Something actually seems very wrong. If I turn heuristics to 1, it hangs in the state shown in the second log for over 48 hours. It seems it has picked a variable to branch on but hasn't finished e...

• Philip Taffet commented,

That's what Gurobi names variables that you don't name yourself. You can provide a more meaningful name when you create the variables.

• Philip Taffet commented,

The mathematical description seems to encode $$|V|*\sum_u C_u$$ constraints, but it looks like you are only creating $$|V|$$ constraints. Could that be the problem?

• Philip Taffet created a post,

### Astronomically low node throughput; major degeneracy?

Hi, I'm trying to diagnose a large MIP model that appears to hang. Unlike previous models that have seemed to hang because they get stuck trying cuts at the root node, this model seems to select a ...

• Philip Taffet commented,

Hi Tobias, Thanks, that makes sense. I'm looking forward to the fix. Thanks, Philip

• Philip Taffet commented,

Your callback can definitely handle multiple where values with if statements.

• Philip Taffet commented,

Solvers — CVX Users' Guide (cvxr.com) has instructions on how to pass parameter settings to Gurobi.  To create a new custom setting for the current solver, use this syntax: cvx_solver_settings(...

• Philip Taffet commented,

Setting Cuts=0, it solves in about an hour, but it still does not seem to be using my heuristic solution, in spite of returning the correct objective from cbUseSolution() Nodes | Current ...

• Philip Taffet commented,

Hi Jaromił, Thanks for the response. I tried the two parameter settings you suggested, and it they did not help. The first MIPNODE callback happened 1300s after the root relaxation finished, and >1...