NumPy ufuncs - Create Your Own Function

To create you own ufunc, you have to define a function, like you do with normal functions in Python, then youadd it to your NumPy ufunc library with the frompyfunc() method

How To Create Your Own ufunc

To create you own ufunc, you have to define a function, like you do with normal functions in Python, then you add it to your NumPy ufunc library with the frompyfunc() method.

The frompyfunc() method takes the following arguments:

  • function - the name of the function.
  • inputs - the number of input arguments (arrays).
  • outputs - the number of output arrays.
  • Example

    Create your own ufunc for addition:

    import numpy as np

    def myadd(x, y):
      return x+y

    myadd = np.frompyfunc(myadd, 2, 1)

    print(myadd([1, 2, 3, 4], [5, 6, 7, 8]))

    Check if a Function is a ufunc

    Check the type of a function to check if it is a ufunc or not.

    A ufunc should return <class 'numpy.ufunc'>.

    Example

    Check if a function is a ufunc:

    import numpy as np

    print(type(np.add))

    If it is not a ufunc, it will return another type, like this built-in NumPy function for joining two or more arrays:

    Example

    Check the type of another function: concatenate():

    import numpy as np

    print(type(np.concatenate))

    If the function is not recognized at all, it will return an error:

    Example

    Check the type of something that does not exist. This will produce an error:

    import numpy as np

    print(type(np.blahblah))

    To test if the function is a ufunc in an if statement, use the numpy.ufunc value (or np.ufunc if you use np as an alias for numpy):

    Example

    Use an if statement to check if the function is a ufunc or not:

    import numpy as np

    if type(np.add) == np.ufunc:
      print('add is ufunc')
    else:
      print('add is not ufunc')