Binary variables with bounds

[mlubin]

How does this interact with variable bounds? I.e., what if you have x == 1, Binary. Does this drop the tighter bounds? I'd also want an error/infeasibility report for 2 <= x <= 3, Binary.

Originally posted by @mlubin in https://github.com/_render_node/MDE3OlB1bGxSZXF1ZXN0UmV2aWV3MTg4NTYwNjMz/pull_request_reviews/more_threads

I couldn't reply to the comment on #76 for some reason, so opening an issue. The current code in #76 seems to silently ignore user-provided bounds on binary variables.

[rschwarz]

What I can do is check for existing bounds. In the case that

• the bounds are already [0,1], there is nothing to do.
• there are no bounds (yet), I can print a warning.
• the bounds are different from [0,1], I will throw an error.

This leaves the possibility that (conflicting) bounds will be added later, which would also be an error.