# Tag Info

### When to use indicator constraints versus big-M approaches in solving (mixed-)integer programs

Here is the advice in the IBM CPLEX documentation. So this pertains to CPLEX. I don't know to what extent it applies to other solvers. First of all, indicator constraints may not be available in all ...
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### When to use indicator constraints versus big-M approaches in solving (mixed-)integer programs

For Gurobi there seems to be a dual advantage of using general constraints (http://www.gurobi.com/documentation/8.1/refman/constraints.html#subsubsection:GeneralConstraints): Benefit number one - ...

### When to use indicator constraints versus big-M approaches in solving (mixed-)integer programs

To the best of my knowledge the indicator constraints are just syntactic sugar for the user. Internally these indicator constraints are reformulated using computed big-M formulations or SOS ...

### When to use indicator constraints versus big-M approaches in solving (mixed-)integer programs

Question by me at the IBM CPLEX Forum: Are indicator constraints immune to trickle flow or other numerics-induced logic "errors"? Are indicator constraints immune to trickle flow or other ...
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### If-then condition formulation to avoid variable multiplication

Something like: \begin{align} & c_i \le x_i + M(1-y_i)\\ & c_i \le My_i \end{align} $M$ can be interpreted as an upperbound on $c_i$. If you don't like the big-$M$'s, consider using ...
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### Formulating the conditional constraint

Let $M_i$ be an upper bound on $Q_i$, and impose linear big-M constraints $0 \le Q_i \le M_i x_i$.
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### Logical equivalencies to modeling an indicator decision variable in transportation problem

Consider the following tiny example. You have two factories, one warehouse and two product. Factory 1 can produce both goods in sufficient quantity to meet demand but has a very large cost coefficient....