Improvements needed for feasibility based bounds tightening

Pyomo / pyomo

An object-oriented algebraic modeling language in Python for structured optimization problems.

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Improvements needed for feasibility based bounds tightening #846

Closed carldlaird closed 5 months ago

carldlaird commented 5 years ago

The fbbt module has a list of expressions that it handles. However, this list is not complete (for example, it is missing all the NPV_... expressions and many others). These should be added at some point for completion.

michaelbynum commented 5 years ago

The NPV expressions have been included in #825.

michaelbynum commented 5 years ago

Need to add support for Expressions, and external functions.

michaelbynum commented 5 years ago

1) Add support for more expression types (e.g., external functions). 2) Bounds can probably be improved further when binary variables are encountered. For example, if the upper bound of a binary variable comes out to 0.75, then the value really has to be 0.

michaelbynum commented 5 years ago

I think the remaining expression types that need support are

[ ] ExternalFunctionExpression
[x] LinearExpression
[ ] Expr_ifExpression
[x] AbsExpression
[ ] GetItemExpression

mrmundt commented 6 months ago

@michaelbynum - Can we get an update on this / which expressions still need support?

michaelbynum commented 5 months ago

So, the remaining expression types will just get "skipped", which is fine for now, I think. By skipped, I just mean the bounds will not get improved. I think we can close this.