assert_array_almost_equal_nulp(x, y, nulp=1)[source]¶
Compare two arrays relatively to their spacing.
This is a relatively robust method to compare two arrays whose amplitude is variable.
x, y : array_like
nulp : int, optional
The maximum number of unit in the last place for tolerance (see Notes). Default is 1.
If the spacing between x and y for one or more elements is larger than nulp.
- Check that all items of arrays differ in at most N Units in the Last Place.
- Return the distance between x and the nearest adjacent number.
An assertion is raised if the following condition is not met:
abs(x - y) <= nulps * spacing(maximum(abs(x), abs(y)))
>>> x = np.array([1., 1e-10, 1e-20]) >>> eps = np.finfo(x.dtype).eps >>> np.testing.assert_array_almost_equal_nulp(x, x*eps/2 + x)
>>> np.testing.assert_array_almost_equal_nulp(x, x*eps + x) Traceback (most recent call last): ... AssertionError: X and Y are not equal to 1 ULP (max is 2)