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

Antoine Pitrou solipsis at pitrou.net
Sat Oct 5 23🔞07 CEST 2013

On Sun, 06 Oct 2013 00:02:14 +0300 Serhiy Storchaka <storchaka at gmail.com> wrote:

05.10.13 23:11, Georg Brandl написав(ла): > 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 just need something to which I can refer in similar situations (there was several similar rejected proposition last months).

Sometimes there are no hard rules, and several factors can combine into a decision. Complexity of implementation and existing alternatives are useful guidelines, IMHO.

Optimized "+=" for strings has been re-enabled after PEP 393, IIRC.

Regards

Antoine.

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