On 12/04/2012 09:31 PM, Jason Grout wrote:
> On 12/4/12 6:07 PM, Michael Orlitzky wrote:
>> On 12/04/2012 07:01 PM, Tom Boothby wrote:
>>> prod() does just what you want.
>>>
>>
>> Duh, thanks. I swear I tried produ<tab>.
>>
>
> Just FYI, the prod() function assumes your multiplication is associative
> and often does a balanced multiplication. This can be significantly
> faster than the operator.reduce version you mention, but it also can
> behave differently in corner cases (like non-associative
> multiplication). Do prod? to see details.
>
Thanks, I did read the implementation and try to beat it out of
curiosity. The only obvious win I found for the simple algorithm is with
symbols,
sage: from functools import reduce
sage: def simple_prod(xs):
....: return reduce(operator.mul, xs, 1)
....:
sage: a = SymbolSequence('a')
sage: xs = [k*a[k] for k in range(0,100)]
sage: timeit('simple_prod(xs)')
625 loops, best of 3: 324 盜 per loop
sage: timeit('prod(xs)')
625 loops, best of 3: 524 盜 per loop
But the performance is irrelevant to me anyway. I still have it defined
in my init.sage, but now it's just,
product = prod
so I don't stumble about trying to remember the name next time.
--
You received this message because you are subscribed to the Google Groups
"sage-devel" group.
To post to this group, send email to sage-devel@googlegroups.com.
To unsubscribe from this group, send email to
sage-devel+unsubscr...@googlegroups.com.
Visit this group at http://groups.google.com/group/sage-devel?hl=en.
