return cost_dual in the solution

[wjzhou-ep]

Thank you for the project. It is both fast and stable for our usage.

Could we add the cost_dual in the solution? (and the Python API )

Clarabel.rs/src/solver/implementations/default/solution.rs

Line 61 in b6f7bf9

self.obj_val = info.cost_primal;

Clarabel.rs/src/python/impl_default_py.rs

Line 68 in b6f7bf9

obj_val: result.obj_val,

Use case:
Sometimes, we got AlmostSolved. Currently, we print a warning message for ourselves and recheck manually later.

However, from the the value returned in solution, we don't know the tol_gap, so we would need to regenerate the whole data and re-run the solver with verbose=True to get the that information.

Ideally, we would like to investigate cases that has wider gap, e.g. we would like to check cases with 5e-5 gap instead of 1.1e-8 case. But currently, we would have to run the solver again first to know that.

Another benefit is that, we probably can downgrade the 1e-7 case from warning to info. (We still want to keep the 1e-8 for tol_gap so the solver tries harder instead of declare optimal at 1e-7)

[wjzhou]

Thank you for fixing this so quickly.