`numpy.testing._private.utils:assert_array_almost_equal_nulp`

Signature

def assert_array_almost_equal_nulp ( x , y , nulp = 1 )

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: Input arrays.
nulp : int, optional: The maximum number of unit in the last place for tolerance (see Notes). Default is 1.

: AssertionError: If the spacing between x and y for one or more elements is larger than nulp.

An assertion is raised if the following condition is not met

abs(x - y) <= nulp * 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)