actuary77 wrote:
Recurse from 9999 time: 4.3059999942779541 seconds
Iter from 9999 time: 0.0099999904632568359 seconds
No comparison, why is recursion so slow?
I usually don't delve too deeply into language design issues, so I hope others will correct me if I'm wrong. Recursion is usually slower than the equivalent iteration unless if it is specifically optimized by the language implementation. Most Schemes, for example, do tail-call optimization, and so many uses of recursion run pretty fast. CPython is not one of those implementations.
Would using a generator be faster than recursion?
Try it.
I really have complex list comprehension.
Then you shouldn't be using list comprehensions.
I am interating n times. I have initial function: func(x) I have initial seed value: _aseed
iteration value 1 func(_aseed) 2 func(func(_aseed)) .... n func(func(func...........(_aseed))
What would be the fastest way to do this?
Non-generator: def f1(aseed): values = [func(aseed)] for i in range(n-1): values.append(func(values[-1])) return values
Generator:
def f2(aseed):
value = func(aseed)
for i in range(n):
yield value
value = func(aseed)Probably not *the* fastest solutions, but I'll wager that the speed gains you get from a faster solution will be more than paid for by a loss in clarity.
Do the simplest thing that could possibly work. Don't bother with trickier/less Pythonic approaches until they're really called for.
-- Robert Kern [EMAIL PROTECTED]
"In the fields of hell where the grass grows high Are the graves of dreams allowed to die." -- Richard Harter -- http://mail.python.org/mailman/listinfo/python-list
