New submission from Stefan Behnel <stefan...@behnel.de>:
Spelling out the numerator/denominator calculation in the __mod__ special method, and actually implementing __divmod__, speeds up both operations by 2-3x. This is due to avoiding repeated Fraction instantiation and normalisation, as well as less arithmetic operations. $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'a%b' 50000 loops, best of 5: 9.53 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'a%3' 50000 loops, best of 5: 6.61 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'divmod(a, b)' 20000 loops, best of 5: 14.1 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'divmod(a, 3)' 20000 loops, best of 5: 10.2 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'a%b' 100000 loops, best of 5: 2.96 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'a%3' 100000 loops, best of 5: 2.78 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'divmod(a, b)' 100000 loops, best of 5: 3.93 usec per loop $ ./python -m timeit -s 'from fractions import Fraction as F; a = F(-7, 3); b = F(3, 2)' 'divmod(a, 3)' 50000 loops, best of 5: 3.82 usec per loop ---------- components: Library (Lib) messages: 332533 nosy: scoder priority: normal severity: normal status: open title: Speed up mod/divmod for Fraction type type: performance versions: Python 3.8 _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue35588> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
