Terry Reedy, 25.03.2011 21:18:
On 3/25/2011 5:16 AM, Stefan Behnel wrote:
Terry's version is playing with the fact that default arguments are only
instantiated once, i.e. (unless overridden by passing an explicit
argument) the "_cache" is shared over all calls to the function. This is
similar to what your memoization decorator does, but without the
additional dict. And, it also "suffers" from the same timing problem
that I mentioned before.
It depends on what one wants to measure. If one is memoizing because one
expects to call the function 1000s of times in some program, then the fast
lookup time of repeated calls represents the actual post-initialization
burden on that program. If one want to measure the initialization time,
then the cache can easily be restarted with each call (once one knows how):
fib_iter(100,_cache=[0,1])
Not "restarted" in the sense that it gets cleaned up, though. The above
simply passes an explicit value for it that will be used for the single
call. Future calls won't be affected.
Stefan
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