Picking the most efficient flower-picking route with simulated annealing

I spent last week working on a new projet, which involved generating networks
with fixed structural properties. I experimented with some approaches, but
simulated annealing gave by far the best results. I thought it would be a nice
opportunity to aggregate some notes and code here. We will see the way
temperature decreases to constrain optimization, how to decide on accepting a
change of state as a function of temperature, and then an illustration on
species occurrence data.