Greg Glockner
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Activity overview
Latest activity by Greg Glockner-
Greg Glockner commented,
Official comment Gurobi uses standard mixed-integer programming (MIP) techniques: it solves MIP models via a series of continuous (linear programming) relaxations. All variables are therefore continuous (double) va...
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Greg Glockner commented,
Sure: use ranges rather than numbers, for example: x = model.addVars(range(1,3), range(1,4), name="x")
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Greg Glockner commented,
If you want to remove a constraint and add it later, you need to get the elements of a constraint. For a linear constraint, it looks like this: c = m.getConstrs()[0] # for examplelhs, sense, rhs, n...
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Greg Glockner commented,
Gurobi does lazy updates to the model. You won't see that this constraint was deleted until the update is processed. To force the update to process immediately, call model.update().
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Greg Glockner commented,
Official comment By default, after solving a MIP, AMPL fixes the integer variables and solves the LP relaxation. This is known as the fixed LP. To prevent this, set the AMPL parameter basis=1.
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Greg Glockner commented,
I don't think this has been thoroughly investigated, but I doubt it will work: the Gurobi Python library (gurobipy) uses cython to call the native Gurobi library.
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Greg Glockner commented,
Official comment Thanks. You should enable node files, and look into tuning to reduce the number of nodes.
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Greg Glockner commented,
Please post your logs so that we can understand the model.
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Greg Glockner commented,
Official comment This may be possible but it's not a supported system: An x64 processor is strongly recommended; the x86 processor is deprecated I don't believe Arduino offers an x64 processor You would be better...
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Greg Glockner commented,
In general, whenever you get an infeasible model, it is useful to run IIS, to understand why it is infeasible.