Skip to content

Vague warning for cbc highs dependency. Cannot have Variable objective #452

Open
@RobbieKiwi

Description

@RobbieKiwi
Contributor

Version Checks (indicate both or one)

  • I have confirmed this bug exists on the lastest release of Linopy.

    I have confirmed this bug exists on the current master branch of Linopy.

Issue Description

If you try to use CBC solver without highspy installed you get a vague "NameError"

If you try to pass a variable to add_objective, it gets caught by the type checker

Reproducible Example

# Example 1
import linopy
model = linopy.Model()
x = model.add_variables(name="x", lower=0.0)
model.add_constraints(x >= 0.0)
model.add_objective(x*1.0, sense="min")
model.solve(solver_name="cbc")  # NameError: name 'highspy' is not defined

# Example 2
import linopy
model = linopy.Model()
x = model.add_variables(name="x", lower=0.0)
model.add_constraints(x >= 0.0)
model.add_objective(x, sense="min")  # ValueError: Invalid type of `expr`

Expected Behavior

I expect to get a useful message to say that highspy should be installed to use cbc
I expect to be able to pass a Variable to the add_objective message

Installed Versions

Bottleneck==1.4.2 click==8.1.8 cloudpickle==3.1.1 colorama==0.4.6 dask==2025.4.1 deprecation==2.1.0 fsspec==2025.3.2 linopy==0.5.3 locket==1.0.0 numexpr==2.10.2 numpy==2.2.5 packaging==25.0 pandas==2.2.3 partd==1.4.2 polars==1.29.0 PuLP==3.1.1 python-dateutil==2.9.0.post0 pytz==2025.2 PyYAML==6.0.2 scipy==1.15.2 six==1.17.0 toolz==1.0.0 tqdm==4.67.1 tzdata==2025.2 xarray==2025.4.0

Activity

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Metadata

Metadata

Assignees

No one assigned

    Labels

    bugSomething isn't working

    Type

    No type

    Projects

    No projects

    Milestone

    No milestone

    Relationships

    None yet

      Participants

      @RobbieKiwi

      Issue actions

        Vague warning for cbc highs dependency. Cannot have Variable objective · Issue #452 · PyPSA/linopy