CVXPYBackend: Implement remove_constraint[s] methods

[takshakmudgal]

📚 Description

Adding the missing remove_constraint method to the CVXPYBackend library. The remove_constraint method takes an index of the constraint to remove. It removes the corresponding row from the matrix, as well as the lower and upper bounds and the constraint name. Finally, it updates the problem attribute of the solver with a new list of constraints.

Fixes #35369

📝 Checklist

• The title is concise, informative, and self-explanatory.
• The description explains in detail what this PR is about.
• I have linked a relevant issue or discussion.
• I have created tests covering the changes.
• I have updated the documentation accordingly.

[mkoeppe]

I am getting

[sagelib-10.0.beta8]     Error compiling Cython file:
[sagelib-10.0.beta8]     ------------------------------------------------------------
[sagelib-10.0.beta8]     ...
[sagelib-10.0.beta8]             if value is not False:
[sagelib-10.0.beta8]                 self.col_lower_bound[index] = value
[sagelib-10.0.beta8]             else:
[sagelib-10.0.beta8]                 return self.col_lower_bound[index]
[sagelib-10.0.beta8] 
[sagelib-10.0.beta8]         cpdef remove_constraint(self, index):
[sagelib-10.0.beta8]              ^
[sagelib-10.0.beta8]     ------------------------------------------------------------
[sagelib-10.0.beta8] 
[sagelib-10.0.beta8]     sage/numerical/backends/cvxpy_backend.pyx:936:10: Signature not compatible with previous declaration
[sagelib-10.0.beta8] 
[sagelib-10.0.beta8]     Error compiling Cython file:
[sagelib-10.0.beta8]     ------------------------------------------------------------
[sagelib-10.0.beta8]     ...
[sagelib-10.0.beta8]         cpdef objective_constant_term(self, d=*)
[sagelib-10.0.beta8]         cpdef set_objective(self, list coeff, d=*)
[sagelib-10.0.beta8]         cpdef set_verbosity(self, int level)
[sagelib-10.0.beta8]         cpdef add_linear_constraint(self, coefficients, lower_bound, upper_bound, name=*)
[sagelib-10.0.beta8]         cpdef add_linear_constraint_vector(self, degree, coefficients, lower_bound, upper_bound, name=*)
[sagelib-10.0.beta8]         cpdef remove_constraint(self, int)
[sagelib-10.0.beta8]                                ^
[sagelib-10.0.beta8]     ------------------------------------------------------------

[mkoeppe]

The Lint errors are unrelated; ignore.

[github-actions]

Documentation preview for this PR is ready! 🎉
Built with commit: aecb190

[kwankyu]

What happened to this PR? Please add an appropriate resolution label.

[mkoeppe]

It has been merged into #35368