For anyone familiar with the Pyomo book, it occasionally makes reference to the AMPL Solver Library, and to my understanding, if you can manage to hook up to the solver library then you are able to use those particular solvers. However, I am confused because I am interpreting the idea of the AMPL Solver Library as open source in a similar way as to how you can just use NEOS as a "Solver Manager" and then get access to various solvers that way.
The way that I understand how solvers work is that you can either 'hook up' to something like the NEOS Server and then use the available solvers, or you can download the solvers locally and use those somehow. It's a crude understanding, but how exactly we connect to the solvers is still something I am trying to wrap my head around.
Would you first need to purchase the solver - knitro for example - and then we can use the knitro solver through the AMPL library? Or, if we interface through the AMPL library (like we can do with NEOS) then we can use knitro for free?