测试浮点平等 [英] Testing floating point equality

问题描述

有一个函数来测试浮点近似相等在python吗？类似的东西，

Is there a function to test floating point approximate equality in python? Something like,

 def approx_equal(a, b, tol):
     return abs(a - b) < tol

我的用例类似于Google的C ++测试库gtest.h定义 EXPECT_NEAR 。

My use case is similar to how Google's C++ testing library, gtest.h, defines EXPECT_NEAR.

以下是一个示例：

def bernoulli_fraction_to_angle(fraction):
    return math.asin(sqrt(fraction))
def bernoulli_angle_to_fraction(angle):
    return math.sin(angle) ** 2
def test_bernoulli_conversions():
    assert(approx_equal(bernoulli_angle_to_fraction(pi / 4), 0.5, 1e-4))
    assert(approx_equal(
              bernoulli_fraction_to_angle(bernoulli_angle_to_fraction(0.1)),
                0.1, 1e-4))

推荐答案

• 对于测试数字，有 nose.tools.assert_almost_equal 和等价的 unittest.assertAlmostEqual


• 对于测试数字或数组，有 numpy.testing.assert_allclose


• 数字， math.isclose 按 PEP 485 ，因为Python 3.5。


• 对于比较数字或数组，有 numpy.allclose li>
  
  • For testing numbers, there are nose.tools.assert_almost_equal and equivalently unittest.assertAlmostEqual
  • For testing numbers or arrays, there is numpy.testing.assert_allclose
  • For comparing numbers, there is math.isclose as per PEP 485 since Python 3.5.
  • For comparing numbers or arrays, there is numpy.allclose.

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