[Python-Dev] Optimization (original) (raw)

Antoine Pitrou solipsis at pitrou.net
Sat Oct 5 22:19:48 CEST 2013

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.

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