Adding a Par construct to Python?
steve at REMOVE-THIS-cybersource.com.au
Sun May 17 20:11:57 CEST 2009
On Sun, 17 May 2009 18:24:34 +0200, Diez B. Roggisch wrote:
>> But reduce()? I can't see how you can parallelize reduce(). By its
>> nature, it has to run sequentially: it can't operate on the nth item
>> until it is operated on the (n-1)th item.
> That depends on the operation in question. Addition for example would
You'd think so, but you'd be wrong. You can't assume addition is always
>>> reduce(operator.add, (1.0, 1e57, -1e57))
>>> reduce(operator.add, (1e57, -1e57, 1.0))
> My math-skills are a bit too rusty to qualify the exact nature of
> the operation, commutativity springs to my mind.
And how is reduce() supposed to know whether or not some arbitrary
function is commutative?
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