mirror of
https://github.com/python/cpython
synced 2026-09-27 04:48:18 +03:00
711c80bfca
For converting large ints to strings, CPython invokes a function in _pylong.py, which uses the decimal module to implement an asymptotically waaaaay sub-quadratic algorithm. But if the C decimal module isn't available, CPython uses _pydecimal.py instead. Which in turn frequently does str(int). If the int is very large, _pylong ends up doing the work, which in turn asks decimal to do "big" arithmetic, which in turn calls str(big_int), which in turn ... it can become infinite mutual recursion. This change introduces a different int->str function that doesn't use decimal. It's asymptotically worse, "Karatsuba time" instead of quadratic time, so still a huge improvement. _pylong switches to that when the C decimal isn't available. It is also used for not too large integers (less than 450_000 bits), where it is faster (up to 2 times for 30_000 bits) than the asymptotically better implementation that uses the C decimal. Co-authored-by: Tim Peters <tim.peters@gmail.com> |
||
|---|---|---|
| .. | ||
| NEWS.d | ||
| rhel7 | ||
| ACKS | ||
| coverity_model.c | ||
| externals.spdx.json | ||
| HISTORY | ||
| indent.pro | ||
| platform_triplet.c | ||
| Porting | ||
| python-config.in | ||
| python-config.sh.in | ||
| python-embed.pc.in | ||
| python.man | ||
| python.pc.in | ||
| README | ||
| README.AIX | ||
| README.coverity | ||
| README.valgrind | ||
| sbom.spdx.json | ||
| SpecialBuilds.txt | ||
| stable_abi.toml | ||
| svnmap.txt | ||
| valgrind-python.supp | ||
| vgrindefs | ||
Python Misc subdirectory
========================
This directory contains files that wouldn't fit in elsewhere. Some
documents are only of historic importance.
Files found here
----------------
ACKS Acknowledgements
HISTORY News from previous releases -- oldest last
indent.pro GNU indent profile approximating my C style
NEWS News for this release (for some meaning of "this")
Porting Mini-FAQ on porting to new platforms
python-config.in Python script template for python-config
python.man UNIX man page for the python interpreter
python.pc.in Package configuration info template for pkg-config
README The file you're reading now
README.AIX Information about using Python on AIX
README.coverity Information about running Coverity's Prevent on Python
README.valgrind Information for Valgrind users, see valgrind-python.supp
SpecialBuilds.txt Describes extra symbols you can set for debug builds
svnmap.txt Map of old SVN revs and branches to hg changeset ids,
help history-digging
valgrind-python.supp Valgrind suppression file, see README.valgrind
vgrindefs Python configuration for vgrind (a generic pretty printer)