Pragma Tix:
'Cause the language is not yet stable, therefore the basic library is in flow.
In a simulated annealing algorithm (http://en.wikipedia.org/wiki/Simulated_annealing ) you can't lower the temperature too much quickly, otherwise you get a bad solution. To reach a stable solution you need to lower the temperature progressively and smartly, sometimes you even have to increase it a bit again, before letting the system cool down and reach the stability you look for.
Stochastic optimization strategies offer lot of useful metaphors to express ideas :-)
Bye, bearophile
