nums.numpy.sign

nums.numpy.sign(x, out=None, where=True, **kwargs)[source]

Returns an element-wise indication of the sign of a number.

This docstring was copied from numpy.sign.

Some inconsistencies with the NumS version may exist.

The sign function returns -1 if x < 0, 0 if x==0, 1 if x > 0. nan is returned for nan inputs.

For complex inputs, the sign function returns sign(x.real) + 0j if x.real != 0 else sign(x.imag) + 0j.

complex(nan, 0) is returned for complex nan inputs.

Parameters

x (BlockArray) – Input values.
out (BlockArray, None, or optional) – A location into which the result is stored. If provided, it must have a shape that the inputs broadcast to. If not provided or None, a freshly-allocated array is returned. A tuple (possible only as a keyword argument) must have length equal to the number of outputs.
where (BlockArray, optional) – This condition is broadcast over the input. At locations where the condition is True, the out array will be set to the ufunc result. Elsewhere, the out array will retain its original value. Note that if an uninitialized out array is created via the default out=None, locations within it where the condition is False will remain uninitialized.
**kwargs – For other keyword-only arguments, see the ufunc docs.

Returns

y – The sign of x.

Return type

BlockArray

Notes

There is more than one definition of sign in common use for complex numbers. The definition used here is equivalent to \(x/\sqrt{x*x}\) which is different from a common alternative, \(x/|x|\).

Examples

The doctests shown below are copied from NumPy. They won’t show the correct result until you operate get().

>>> nps.sign(nps.array([-5., 4.5])).get()  
array([-1.,  1.])
>>> nps.sign(nps.array(0)).get()  
array(0)
>>> nps.sign(nps.array(5-2j)).get()  
array(1.+0.j)

nums.numpy.rint

nums.numpy.signbit