Oscar Dowson

I don't really know what I'm talking about, but for the linear case, it seems we just need a matrix multiplication: https://orinanobworld.blogspot.com/2011/07/farkas-certificates-in-cplex.html ```julia get_farkas_dual!(m, m.constraint_dual_solution) A = get_constraint_matrix(m) # doesn't...

I don't think multirow change has been utilised, so there are probably lots of bugs like this. Note that the Gurobi wrapper is being re-written (https://github.com/JuliaOpt/Gurobi.jl/pull/216), and it doesn't implement...

This is failing because it uses GLPK as a solver which uses LQOI. However, thanks to @carlobaldassi: https://github.com/JuliaOpt/LinQuadOptInterface.jl/pull/36, https://github.com/JuliaOpt/GLPK.jl/pull/55

From JuMP or MPB? Which solver? It's worth having a look at the [JuMP implementation](https://github.com/JuliaOpt/JuMP.jl/blob/v0.18.2/src/callbacks.jl). Remember that solver-independent callbacks will no longer be supported in MOI. Instead, you should use...

Are you passing a constraint with a lower-bound of `-Inf` and an upper-bound of `Inf`? Is there any reason to use JuMP 0.18? We'd recommend that you upgrade to JuMP...

It is somewhat ill-defined in MPB. It would be really helpful if you could read http://www.juliaopt.org/MathOptInterface.jl/latest/apireference.html#Basis-Status-1 and http://www.juliaopt.org/MathOptInterface.jl/latest/apireference.html#MathOptInterface.VariableBasisStatus and suggest edits if necessary in order to help clarify things.

A degenerate variable is one in the basis with variable value of 0. Superbasic variables are exactly what is written: [edit: not] in the basis but not at a bound....

Open an issue. I'm not sure how much anyone has actually thought about this part of the API or implemented things.

A `MOI.VectorQuadraticFunction` is a vector of quadratic terms: ```julia model = Model() @variable(model, x[1:2]) @constraint(model, [x[1], x[1]^2 + x[1] * x[2] + 3.0] >= 0) ```

I didn't look at the details, but my only comment is that you might need a `2.0` or a `0.5` factor in there https://github.com/amontoison/NLPModelsJuMP.jl/blob/0b227b47a2ad9c99b4c7c4f9efa569f421295532/src/utils.jl#L322 I don't know if your COO...