Any one had the chance to use pyomo with free/open-source solvers that handle quadratic optimization problems, which they could be convex or not, but preferably as general as possible.
For guaranteed solutions, BONMIN can solve convex MINLPs, and COUENNE can solve general non-convex MINLPs. Both use the ASL (.nl) format, so they work out of the box with Pyomo. IPOPT can also find local optima for non-convex NLP (including quadratic) problems.
$\begingroup$ did you get chance to try them all? what would you recommend to start with? $\endgroup$– BettyMay 19, 2020 at 13:03
1$\begingroup$ Depends on what you want to do, Couenne is the most fool-proof one because it can handle all problem types. $\endgroup$ May 19, 2020 at 15:52