Refactoring variable bounds (min/max/fix)

[mihlema]

During our last call, we talked about possibly refactoring our existing variable bounds. Currently, it is possible to directly fix a variable to a certain value through the fix_variable_name parameters. We could extend this functionality, to also allow the user to force a lower/upper_bound on variables. This way the user can e.g. conveniently define, how many units of a certain type need to be at least invested in. Implementation would be relatively straightforward, populating our workaround for fixing variables and adding min/max_variable_name.
(Related issue #416 )

So far we haven't identified any downsides, except for obviously more parameter definitions.

@Spine-project/spineopt-developers

[clizbe]

@mihlema This is a pretty old discussion. Did we implement it? Can we close the discussion?