[Python-Dev] Accumulation module

[Gareth McCaughan]

On Wednesday 2004-02-25 19:23, Tony Vignaux wrote:

> Raymond,
>
> You asked:
> > * Is there a way to compute the standard deviation without multiple
> > passes over the data (one to compute the mean and a second to sum the
> > squares of the differences from the mean?
>
> I do not understand the problem in getting stdev in a single pass.
> Perhaps I not understood your problem. If you have a series of values
> you merely have to calculate their sum and sum-of-squares and use the
> usual formula.

The trouble with that is that it's numerically horrible.
There are better ways, some of which were discussed in python-dev
a few weeks ago.

-- 
g