numpy.testing.assert_array_almost_equal_nulp — NumPy v2.2 Manual (original) (raw)

testing.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.

Parameters:

x, yarray_like

Input arrays.

nulpint, optional

The maximum number of unit in the last place for tolerance (see Notes). Default is 1.

Returns:

None

Raises:

AssertionError

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

See also

assert_array_max_ulp

Check that all items of arrays differ in at most N Units in the Last Place.

spacing

Return the distance between x and the nearest adjacent number.

Notes

An assertion is raised if the following condition is not met:

abs(x - y) <= nulp * spacing(maximum(abs(x), abs(y)))

Examples

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: Arrays are not equal to 1 ULP (max is 2)