NumPy Tutorial · NumPy ufunc

ufunc Summations

Learn all about ufunc Summations in this comprehensive tutorial.

5 min read advanced

Summations

What is the difference between summation and addition?

Addition is done between two arguments whereas summation happens over n elements.

python

import numpy as nparr1 = np.array([1, 2, 3])arr2 = np.array([1, 2, 
  3])newarr = np.add(arr1, arr2)print(newarr)

Note: Returns: [2 4 6]

python

import numpy as nparr1 = np.array([1, 2, 3])arr2 = np.array([1, 2, 
  3])newarr = np.sum([arr1, arr2])print(newarr)

Note: Returns: 12

If you specify axis=1, NumPy will sum the numbers in each array.

python

import numpy as nparr1 = np.array([1, 2, 3])arr2 = np.array([1, 2, 
  3])newarr = np.sum([arr1, arr2], axis=1)print(newarr)

Note: Returns: [6 6]

Cummulative sum means partially adding the elements in array.

E.g. The partial sum of [1, 2, 3, 4] would be [1, 1+2, 1+2+3, 1+2+3+4] = [1, 3, 6, 10].

Perfom partial sum with the cumsum() function.

python

import numpy as nparr = np.array([1, 2, 3])newarr = np.cumsum(arr)
print(newarr)

Note: Returns: [1 3 6]

2 questions

Which of the following is true about ufunc Summations?

It is strictly typedIt is evaluated at runtimeIt requires explicit memory managementIt is deprecated

What is the most common pitfall when working with ufunc Summations?

SyntaxErrorIndentationErrorNameErrorTypeError

Answer all questions to submit.