explain the condition when results are different
@@ -51,8 +51,9 @@ nextafter = ufunc.create_math_ufunc(
'''Computes the nearest neighbor float values towards the second argument.
.. note::
- Result of :func:`cupy.nextafter` may be different from that of
- :func:`numpy.nextafter` because CuPy sets ``-ftz=true``.
+ For values that are close to zero (or denormal numbers),
+ results of :func:`cupy.nextafter` may be different from those of
+ :func:`numpy.nextafter`, because CuPy sets ``-ftz=true``.
.. seealso:: :data:`numpy.nextafter`
