The Initial Temperature

In general, specifying an initial temperature for annealing is usually a straightforward procedure. Infinite temperature means that the changes are always accepted (i.e. the acceptance ratio is 1), which produces random configurations. In practice the initial temperature should not be too large, or else the cooling will take too long, and the annealing will spend too much time at higher temperatures where little useful work is being done. So the initial temperature is usually chosen to be the lowest possible value that still gives a high acceptance ratio (greater than #tex2html_wrap_inline1866#, for example). Choosing an initial temperature is much more difficult when we use a preprocessor to provide a good starting configuration rather than the usual random initial configuration. In that case, we must be very careful that the initial temperature and the acceptance ratio are not so high that the good initial configuration is randomized to the point where it loses its usefulness leading to inferior final solution or a solution with high cost. However the initial temperature must be high enough so that we can still make effective changes in the configuration. In this set of experimental starting temperatures we have observed that when using the 3 intermediate temperatures, 495, 500 and 505, and particularly 500 for both schedules, the system simulation comes as close as satisfying those criteria, more so than when other temperatures of the set are used.