People have hit on some of the issues, e.g. (a) the algorithm + algorithm must be deterministic (no calls to "random") (b) the computation might be slow because of multiprocessing (time slots scheduled to something else) but also there are other often quite critical issues affecting timing, like:
(c) cache loading / memory interference. The second or subsequent runs may be way faster because all the data and program are now in cache. Is this fair? (d) garbage collection (assuming you are using one of them). Time may be slow because one run includes GC processing. People timing Lisp programs sometimes induce a GC just before a timing run. Of course if the GC causes an additional allocation of memory, the next GC is different etc. I assume there are ways of counting instructions executed (or byte- code interpreted) that may be useful in comparing algorithms that are essentially running in the same environment. This does not mean that the relative speeds will be the same in other environments. RJF -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
