Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

gh-101773: Optimize creation of Fractions in private methods#101780

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to ourterms of service andprivacy statement. We’ll occasionally send you account related emails.

Already on GitHub?Sign in to your account

Merged
mdickinson merged 13 commits intopython:mainfromskirpichev:opt-fractions-new
Feb 27, 2023
Merged
Show file tree
Hide file tree
Changes fromall commits
Commits
Show all changes
13 commits
Select commitHold shift + click to select a range
9cc62f7
gh-101773: Optimize creation of Fraction's in private methods
skirpichevFeb 10, 2023
836d3a6
Merge branch 'main' into opt-fractions-new
skirpichevFeb 10, 2023
3625d34
Adjust signature of _from_pair() and add docstring
skirpichevFeb 11, 2023
9e66b5a
Use new helper in from_float/Decimal
skirpichevFeb 11, 2023
4324391
Restore back _normalize kwarg for the Fraction.__new__()
skirpichevFeb 11, 2023
b0dca38
Amend 3625d34155
skirpichevFeb 11, 2023
3a8506d
Nitpick on docstring (int's -> ints)
skirpichevFeb 27, 2023
13262af
Revert "Restore back _normalize kwarg for the Fraction.__new__()"
skirpichevFeb 27, 2023
4e8977a
Rename: _from_pair -> _from_coprime_ints
skirpichevFeb 27, 2023
57ac373
Merge branch 'main' into opt-fractions-new
skirpichevFeb 27, 2023
4b4a386
Update Misc/NEWS.d/next/Library/2023-02-10-11-59-13.gh-issue-101773.J…
skirpichevFeb 27, 2023
580b1be
+1
skirpichevFeb 27, 2023
53d5e94
Tweak docstring wording
mdickinsonFeb 27, 2023
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
79 changes: 46 additions & 33 deletionsLib/fractions.py
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -183,7 +183,7 @@ class Fraction(numbers.Rational):
__slots__ = ('_numerator', '_denominator')

# We're immutable, so use __new__ not __init__
def __new__(cls, numerator=0, denominator=None, *, _normalize=True):
def __new__(cls, numerator=0, denominator=None):
"""Constructs a Rational.

Takes a string like '3/2' or '1.5', another Rational instance, a
Expand DownExpand Up@@ -279,12 +279,11 @@ def __new__(cls, numerator=0, denominator=None, *, _normalize=True):

if denominator == 0:
raise ZeroDivisionError('Fraction(%s, 0)' % numerator)
if _normalize:
g = math.gcd(numerator, denominator)
if denominator < 0:
g = -g
numerator //= g
denominator //= g
g = math.gcd(numerator, denominator)
if denominator < 0:
g = -g
numerator //= g
denominator //= g
self._numerator = numerator
self._denominator = denominator
return self
Expand All@@ -301,7 +300,7 @@ def from_float(cls, f):
elif not isinstance(f, float):
raise TypeError("%s.from_float() only takes floats, not %r (%s)" %
(cls.__name__, f, type(f).__name__))
return cls(*f.as_integer_ratio())
return cls._from_coprime_ints(*f.as_integer_ratio())

@classmethod
def from_decimal(cls, dec):
Expand All@@ -313,7 +312,19 @@ def from_decimal(cls, dec):
raise TypeError(
"%s.from_decimal() only takes Decimals, not %r (%s)" %
(cls.__name__, dec, type(dec).__name__))
return cls(*dec.as_integer_ratio())
return cls._from_coprime_ints(*dec.as_integer_ratio())

@classmethod
def _from_coprime_ints(cls, numerator, denominator, /):
"""Convert a pair of ints to a rational number, for internal use.

The ratio of integers should be in lowest terms and the denominator
should be positive.
"""
obj = super(Fraction, cls).__new__(cls)
obj._numerator = numerator
obj._denominator = denominator
return obj

def is_integer(self):
"""Return True if the Fraction is an integer."""
Expand DownExpand Up@@ -380,9 +391,9 @@ def limit_denominator(self, max_denominator=1000000):
# the distance from p1/q1 to self is d/(q1*self._denominator). So we
# need to compare 2*(q0+k*q1) with self._denominator/d.
if 2*d*(q0+k*q1) <= self._denominator:
return Fraction(p1, q1, _normalize=False)
return Fraction._from_coprime_ints(p1, q1)
else:
return Fraction(p0+k*p1, q0+k*q1, _normalize=False)
return Fraction._from_coprime_ints(p0+k*p1, q0+k*q1)

@property
def numerator(a):
Expand DownExpand Up@@ -703,13 +714,13 @@ def _add(a, b):
nb, db = b._numerator, b._denominator
g = math.gcd(da, db)
if g == 1:
return Fraction(na * db + da * nb, da * db, _normalize=False)
return Fraction._from_coprime_ints(na * db + da * nb, da * db)
s = da // g
t = na * (db // g) + nb * s
g2 = math.gcd(t, g)
if g2 == 1:
return Fraction(t, s * db, _normalize=False)
return Fraction(t // g2, s * (db // g2), _normalize=False)
return Fraction._from_coprime_ints(t, s * db)
return Fraction._from_coprime_ints(t // g2, s * (db // g2))

__add__, __radd__ = _operator_fallbacks(_add, operator.add)

Expand All@@ -719,13 +730,13 @@ def _sub(a, b):
nb, db = b._numerator, b._denominator
g = math.gcd(da, db)
if g == 1:
return Fraction(na * db - da * nb, da * db, _normalize=False)
return Fraction._from_coprime_ints(na * db - da * nb, da * db)
s = da // g
t = na * (db // g) - nb * s
g2 = math.gcd(t, g)
if g2 == 1:
return Fraction(t, s * db, _normalize=False)
return Fraction(t // g2, s * (db // g2), _normalize=False)
return Fraction._from_coprime_ints(t, s * db)
return Fraction._from_coprime_ints(t // g2, s * (db // g2))

__sub__, __rsub__ = _operator_fallbacks(_sub, operator.sub)

Expand All@@ -741,15 +752,17 @@ def _mul(a, b):
if g2 > 1:
nb //= g2
da //= g2
return Fraction(na * nb, db * da, _normalize=False)
return Fraction._from_coprime_ints(na * nb, db * da)

__mul__, __rmul__ = _operator_fallbacks(_mul, operator.mul)

def _div(a, b):
"""a / b"""
# Same as _mul(), with inversed b.
na, da = a._numerator, a._denominator
nb, db = b._numerator, b._denominator
if nb == 0:
raise ZeroDivisionError('Fraction(%s, 0)' % db)
na, da = a._numerator, a._denominator
g1 = math.gcd(na, nb)
if g1 > 1:
na //= g1
Expand All@@ -761,7 +774,7 @@ def _div(a, b):
n, d = na * db, nb * da
if d < 0:
n, d = -n, -d
return Fraction(n, d, _normalize=False)
return Fraction._from_coprime_ints(n, d)

__truediv__, __rtruediv__ = _operator_fallbacks(_div, operator.truediv)

Expand DownExpand Up@@ -798,17 +811,17 @@ def __pow__(a, b):
if b.denominator == 1:
power = b.numerator
if power >= 0:
return Fraction(a._numerator ** power,
a._denominator ** power,
_normalize=False)
elif a._numerator >= 0:
return Fraction(a._denominator ** -power,
a._numerator ** -power,
_normalize=False)
return Fraction._from_coprime_ints(a._numerator ** power,
a._denominator ** power)
elif a._numerator > 0:
return Fraction._from_coprime_ints(a._denominator ** -power,
a._numerator ** -power)
elif a._numerator == 0:
raise ZeroDivisionError('Fraction(%s, 0)' %
a._denominator ** -power)
else:
return Fraction((-a._denominator) ** -power,
(-a._numerator) ** -power,
_normalize=False)
return Fraction._from_coprime_ints((-a._denominator) ** -power,
(-a._numerator) ** -power)
else:
# A fractional power will generally produce an
# irrational number.
Expand All@@ -832,15 +845,15 @@ def __rpow__(b, a):

def __pos__(a):
"""+a: Coerces a subclass instance to Fraction"""
return Fraction(a._numerator, a._denominator, _normalize=False)
return Fraction._from_coprime_ints(a._numerator, a._denominator)

def __neg__(a):
"""-a"""
return Fraction(-a._numerator, a._denominator, _normalize=False)
return Fraction._from_coprime_ints(-a._numerator, a._denominator)

def __abs__(a):
"""abs(a)"""
return Fraction(abs(a._numerator), a._denominator, _normalize=False)
return Fraction._from_coprime_ints(abs(a._numerator), a._denominator)

def __int__(a, _index=operator.index):
"""int(a)"""
Expand Down
1 change: 1 addition & 0 deletionsLib/test/test_fractions.py
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -488,6 +488,7 @@ def testArithmetic(self):
self.assertEqual(F(5, 6), F(2, 3) * F(5, 4))
self.assertEqual(F(1, 4), F(1, 10) / F(2, 5))
self.assertEqual(F(-15, 8), F(3, 4) / F(-2, 5))
self.assertRaises(ZeroDivisionError, operator.truediv, F(1), F(0))
self.assertTypedEquals(2, F(9, 10) // F(2, 5))
self.assertTypedEquals(10**23, F(10**23, 1) // F(1))
self.assertEqual(F(5, 6), F(7, 3) % F(3, 2))
Expand Down
2 changes: 1 addition & 1 deletionLib/test/test_numeric_tower.py
View file
Open in desktop
Original file line numberDiff line numberDiff line change
Expand Up@@ -145,7 +145,7 @@ def test_fractions(self):
# The numbers ABC doesn't enforce that the "true" division
# of integers produces a float. This tests that the
# Rational.__float__() method has required type conversions.
x = F(DummyIntegral(1), DummyIntegral(2), _normalize=False)
x = F._from_coprime_ints(DummyIntegral(1), DummyIntegral(2))
self.assertRaises(TypeError, lambda: x.numerator/x.denominator)
self.assertEqual(float(x), 0.5)

Expand Down
View file
Open in desktop
Original file line numberDiff line numberDiff line change
@@ -0,0 +1,2 @@
Optimize :class:`fractions.Fraction` for small components. The private argument
``_normalize`` of the :class:`fractions.Fraction` constructor has been removed.
[8]ページ先頭
©2009-2025 Movatter.jp