[Swift-devel] Use case and examples needed to avoid large directories

[Mihael Hategan]

On Sun, 2007-09-30 at 19:48 +0000, Ben Clifford wrote:
> 
> On Sun, 30 Sep 2007, Michael Wilde wrote:
> 
> > examples, where softmean needs to average a large set of inputs, and its
> > behavior is, we thing, associatve.
> 
> mean as an operator is not usually associative - I'd think softmean isn't 
> either if its doing per-pixel arithmetic means, which is what I've always 
> assumed it was doing.
> 
> (e.g.   (1 mean 2) mean 3) = (( (1+2)/2) + 3)/2 = 2.25
>         1 mean (2 mean 3) = ( 1 + ( (2+3)/2) ) /2 = 1.75
> 
> and neither are the actual mean of (1,2,3) which is 2.

... assuming the operation is associative.

In this case perhaps the mean, on whatever group, may very well be
defined as (x1 + x2 + ... + xn)/n. If we have access to "+" and "/",
then it should be fine.

>