[issue41310] micro-optimization: increase our float parsing speed by Nx

Antoine Pitrou added the comment: FTR, no formal description of the algorithm seems to have been published, but the source code is amply commented: https://github.com/lemire/fast_double_parser/blob/master/include/fast_double_parser.h -- nosy: +pitrou

[issue41310] micro-optimization: increase our float parsing speed by Nx

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[issue41310] micro-optimization: increase our float parsing speed by Nx

Eric V. Smith added the comment: I don't think we'd want to fall back to strtod, but rather to the code we already use (Gay's). So this would increase our maintenance burden. I'm also not convinced that we actually spend a lot of time in this code, but of course profiling would be needed to

[issue41310] micro-optimization: increase our float parsing speed by Nx

Tim Peters added the comment: Gregory, care to take their code and time it against Python? I'm not inclined to: reading the comments in the code, they're trying "fast paths" already described in papers by Clinger and - later - by Gay. When those fast paths don't apply, they fall back on

[issue41310] micro-optimization: increase our float parsing speed by Nx

Mark Dickinson added the comment: Is there a description of the algorithms or ideas used anywhere? The blog post you link to has no details, and I don't see any useful descriptions in the GitHub README or the source; trawling through the source to figure out what the key ideas are is not

[issue41310] micro-optimization: increase our float parsing speed by Nx

Serhiy Storchaka added the comment: CPython is written on C, not C++, so we cannot use std::from_chars. Note also that to parse a number in JSON we need first to scan the PyUnicode object character-by-character using PyUnicode_READ() which is slower than just reading a byte from a memory,

[issue41310] micro-optimization: increase our float parsing speed by Nx

Change by Raymond Hettinger : -- nosy: +rhettinger, tim.peters ___ Python tracker ___ ___ Python-bugs-list mailing list

[issue41310] micro-optimization: increase our float parsing speed by Nx

Change by Eric V. Smith : -- nosy: +eric.smith, mark.dickinson ___ Python tracker ___ ___ Python-bugs-list mailing list

[issue41310] micro-optimization: increase our float parsing speed by Nx

New submission from Gregory P. Smith : See https://lemire.me/blog/2020/03/10/fast-float-parsing-in-practice/ for inspiration and a reference (possibly a library to use, but if not the techniques still apply). Primarily usable when creating the float objects from the string data as is common