mirror of
https://github.com/python/cpython.git
synced 2025-10-30 21:21:22 +00:00
6e39fa1955
This PR updates `math.nextafter` to add a new `steps` argument. The behaviour is as though `math.nextafter` had been called `steps` times in succession. --------- Co-authored-by: Mark Dickinson <mdickinson@enthought.com>
41 lines
1.2 KiB
Python
41 lines
1.2 KiB
Python
import functools
|
|
import unittest
|
|
from math import isnan, nextafter
|
|
from test.support import requires_IEEE_754
|
|
from test.support.hypothesis_helper import hypothesis
|
|
|
|
floats = hypothesis.strategies.floats
|
|
integers = hypothesis.strategies.integers
|
|
|
|
|
|
def assert_equal_float(x, y):
|
|
assert isnan(x) and isnan(y) or x == y
|
|
|
|
|
|
def via_reduce(x, y, steps):
|
|
return functools.reduce(nextafter, [y] * steps, x)
|
|
|
|
|
|
class NextafterTests(unittest.TestCase):
|
|
@requires_IEEE_754
|
|
@hypothesis.given(
|
|
x=floats(),
|
|
y=floats(),
|
|
steps=integers(min_value=0, max_value=2**16))
|
|
def test_count(self, x, y, steps):
|
|
assert_equal_float(via_reduce(x, y, steps),
|
|
nextafter(x, y, steps=steps))
|
|
|
|
@requires_IEEE_754
|
|
@hypothesis.given(
|
|
x=floats(),
|
|
y=floats(),
|
|
a=integers(min_value=0),
|
|
b=integers(min_value=0))
|
|
def test_addition_commutes(self, x, y, a, b):
|
|
first = nextafter(x, y, steps=a)
|
|
second = nextafter(first, y, steps=b)
|
|
combined = nextafter(x, y, steps=a+b)
|
|
hypothesis.note(f"{first} -> {second} == {combined}")
|
|
|
|
assert_equal_float(second, combined)
|