I am using the solver "Minimize Facilities" in the location allocation toolbox, but there is a constraint in my problem the solver doesn't allow me to add it. The constraint is for some nodes, the total demand connected to that specific node is n-1, where n is the total number of nodes or lines connected to that node from the neighbor. This is an extra constraint but I couldn't find any way to include it in my problem.

I found a python package called PuLP used for linear programming optimization. Has anyone used it before? Any other toolboxes that can be used for this problem with an option to add mathematic constraints?

Thanks in advance

You can use Network Analyse with external LP solvers using PuLP. An example to do an allocation by first computing the travel cost matrix in ArcMap is here:

http://www.arcgis.com/home/item.html?id=c5ae481f25604d1bb050d9bd1d6e3c06

Jay Sandhu