[Python-Dev] FAT Python (lack of) performance

[Stephen J. Turnbull]

Terry Reedy writes:
 > On 1/26/2016 12:02 AM, INADA Naoki wrote:
 > 
 > > People use same algorithm on every language when compares base language
 > > performance [1].
 > 
 > The python code is NOT using the same algorithm.  The proof is that the 
 > Python function will return the correct value for, say fib(50) while 
 > most if not all the other versions will not.

True, but that's not a reasonable criterion for "same algorithm" in
this context.  Naoki's application ("base language performance"
benchmarking) requires fib(n) only for n < 40, and run it in a loop
100 times if you want 2 more decimal places of precision ("40" is
appropriate for an implementation with 32-bit ints).  On that
restricted domain the algorithm *is* the same.

If you want to argue that the bigger domain is a better one to use for
evaluating programming languages, be our guest.  But then you're
comparing apples (speed) to oranges (domain), and Naoki (or the
Japanese benchmarkers) can argue that a smaller, more risky, domain is
covered by "consenting adults" -- if you know there's a risk, you need
to write code to deal with it, but if you know there isn't, you
shouldn't have to accept lower performance.

Obviously, I don't think that's an appropriate tradeoff myself, but
that's based on "IMHO" not "comparison is invalid because algorithms
differ".