Quadratic absolute object function can't be solved by the solver

[Jingru923]

What
After using equal constraint for flow conservation (PR: #1083), a bug appeared in allocation_test.jl. When using quadratic absolute as object function, minimal subnetwork as test model, the solver give error of

Termination status : OTHER_ERROR
  Message from the solver:
  "There was an error calling optimize!"

The reason of the error is unknown. When I print out the optimization problem, I notice the redundant constraints. If I simplify the constraints, I can solve it with help of some online tools. This means that this optimization problem is feasible, but somehow the solver HiGHS can't deal with it.

How

Some possible ways to solve this issue and will be :

• Try problem with other solvers
• Try problem with HiGHS but redundant constraints removed
• Contact developer of HiGHS with problem (make issue)

[visr]

Here is a relevant JuMP issue about redundant constraints: jump-dev/JuMP.jl#1799

[Jingru923]

The issue #1191 make this one no longer applicable. So this issue is closed.