I’d like to calculate the slacks for a quadratic constraint. Using MathProgBase.getconstrmatrix (see old Google Groups post) does not work for quadratic constraints. Any suggestions?

# Calculate slacks for quadratic constraints

**miles.lubin**#2

MathProgBase doesn’t currently have a method to query the quadratic parts of a model. Your options are:

- Propose a new MathProgBase method and implement it for the solvers you need.
- Write a dummy solver to capture the model data from
`JuMP.build()`

. - Extract the quadratic model data from JuMP’s data structures (example).
- Remember which quadratic terms you added to the JuMP model in the first place.

**adowling2**#3

@miles.lubin Thank you for the suggestion. I’ll try 2 and/or 3 and update with my progress.