Matthias Miltenberger

Gurobi Staff Gurobi Staff

Gurobi Optimization Support Manager - Berlin, Germany

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Activity overview

Latest activity by Matthias Miltenberger
  • Matthias Miltenberger commented,

    Hi Timo, I may be missing something here, but why are you interested in explicitly removing those variables from the objective function? They will just be ignored when the model is read. File sizes...

  • Matthias Miltenberger commented,

    Hi! There have been indeed some updates to the tupledict and tuplelist implementations in version 11 to make them more Pythonic. Here's the list of updates: Release Notes for Gurobi 11.0 Our docume...

  • Matthias Miltenberger commented,

    Hi Selin, This is likely a problem with your LOCALE settings. Maybe you can fix the issue by trying export LC_ALL="en_US.UTF-8" before running the grbgetkey command (but this really depends on your...

  • Matthias Miltenberger commented,

    Hi Shesha, a=9 and b=32 is a perfectly valid solution to the problem. To enforce that Gurobi selects a solution that minimizes the remainder b, you need to specify exactly that and add b to your ob...

  • Matthias Miltenberger commented,

    You can use our matrix-friendly API to get rid of most of the overhead when building these constraints: x = m.addMVar((num_works, num_experts), vtype=GRB.BINARY, name="x")z = m.addMVar((num_experts...

  • Matthias Miltenberger commented,

    Hi! The problematic part of this model is this: for i in range(num_experts):   for k in range(num_experts):       if i != k:             m.addConstr(z[i, k] == gp.quicksum(x[j, i] * x[j, k] for...

  • Matthias Miltenberger commented,

    You could try using a different setting of parameter PreQLinearize for QUBOs. This should help with larger models. The gap is computed as usual. It's just the relative difference between the incumb...

  • Matthias Miltenberger commented,

    Hi Timo, Is there a reason you cannot use something like this (assuming Python is used in your code): env = gp.Env(empty=True)logFile = os.getenv("GRB_LOGFILE", "gurobi.log")env.setParam("LogFile",...

  • Matthias Miltenberger commented,

    Hi Marco, There is a fundamental difference between (user) cuts and lazy constraints. This is explained here: What is the difference between user cuts and lazy constraints? Essentially, user cuts m...

  • Matthias Miltenberger commented,

    Hi, You can get the min and max values for \(\Delta b\) by querying these two linear constraint attributes after the model has been solved to optimality and a basic solution is available: SARHSLow...