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{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Optimize creation of unnormalized Fraction's in private methods (arithmetics, etc)","articleBody":"Right now we just use `__new__()` with a private kwarg `_normalize=False`.  That's slightly less efficient, then a dedicated class method.\r\n\r\nPOC patch\r\n---------------\r\n```diff\r\ndiff --git a/Lib/fractions.py b/Lib/fractions.py\r\nindex 49a3f2841a..27c75785fb 100644\r\n--- a/Lib/fractions.py\r\n+++ b/Lib/fractions.py\r\n@@ -315,6 +315,13 @@ def from_decimal(cls, dec):\r\n                 (cls.__name__, dec, type(dec).__name__))\r\n         return cls(*dec.as_integer_ratio())\r\n \r\n+    @classmethod\r\n+    def _from_pair(cls, num, den):\r\n+        obj = super(Fraction, cls).__new__(cls)\r\n+        obj._numerator = num\r\n+        obj._denominator = den\r\n+        return obj\r\n+\r\n     def is_integer(self):\r\n         \"\"\"Return True if the Fraction is an integer.\"\"\"\r\n         return self._denominator == 1\r\n@@ -703,13 +710,13 @@ def _add(a, b):\r\n         nb, db = b._numerator, b._denominator\r\n         g = math.gcd(da, db)\r\n         if g == 1:\r\n-            return Fraction(na * db + da * nb, da * db, _normalize=False)\r\n+            return Fraction._from_pair(na * db + da * nb, da * db)\r\n         s = da // g\r\n         t = na * (db // g) + nb * s\r\n         g2 = math.gcd(t, g)\r\n         if g2 == 1:\r\n-            return Fraction(t, s * db, _normalize=False)\r\n-        return Fraction(t // g2, s * (db // g2), _normalize=False)\r\n+            return Fraction._from_pair(t, s * db)\r\n+        return Fraction._from_pair(t // g2, s * (db // g2))\r\n \r\n     __add__, __radd__ = _operator_fallbacks(_add, operator.add)\r\n \r\n```\r\nWe can drop private kwarg of `__new__()` after adopting this way.\r\n\r\nSome benchmarks\r\n-----------------\r\n\r\nWith above patch\r\n```\r\n$ ./python -m timeit -s 'from fractions import Fraction as Q' -s 'a,b=Q(3,7),Q(5, 8)' -u usec 'a+b'\r\n50000 loops, best of 5: 4.4 usec per loop\r\n$ ./python -m timeit -s 'from fractions import Fraction as Q' -s 'a,b=Q(3,7)**100,Q(5, 8)**100' -u usec 'a+b'\r\n20000 loops, best of 5: 12.6 usec per loop\r\n```\r\nOn the ~~master~~main:\r\n```\r\n$ ./python -m timeit -s 'from fractions import Fraction as Q' -s 'a,b=Q(3,7),Q(5, 8)' -u usec 'a+b'\r\n50000 loops, best of 5: 6.99 usec per loop\r\n$ ./python -m timeit -s 'from fractions import Fraction as Q' -s 'a,b=Q(3,7)**100,Q(5, 8)**100' -u usec 'a+b'\r\n20000 loops, best of 5: 15.9 usec per loop\r\n```\n\n\u003c!-- gh-linked-prs --\u003e\n### Linked PRs\n* gh-101780\n\u003c!-- /gh-linked-prs --\u003e\n","author":{"url":"https://github.com/skirpichev","@type":"Person","name":"skirpichev"},"datePublished":"2023-02-10T06:49:53.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":1},"url":"https://github.com/101773/cpython/issues/101773"}