[Python-Dev] Optimization

[Antoine Pitrou]

On Sat, 05 Oct 2013 22:11:43 +0200
Georg Brandl <g.brandl at gmx.net> wrote:
> Am 05.10.2013 21:42, schrieb Serhiy Storchaka:
> > Please remember me, what was common decision about CPython-only 
> > optimizations which change computation complexity? I.g. constant 
> > amortization time of += for byte objects and strings, or linear time of 
> > sum() for sequences?
> 
> This appears to be about changeset 499a96611baa:
> 
>   Issue #19087: Improve bytearray allocation in order to allow cheap popping of
> data at the front (slice deletion).
> 
> I think the best way to describe the CPython strategy is that we don't like to
> optimize things that both have an idiomatic solution already (see str.join) and
> can't be replicated easily in other implementations.

Agreed with this. I'll also point out that algorithmic complexity is
only an aspect of performance.

For example, providing a fast C implementation of decimal is a game
changer even though algorithmic complexity may have remained identical.

Regards

Antoine.