numpy.einsum() Method

In NumPy, we can find Einstein’s summation convention of two given multidimensional arrays with the help of numpy.einsum(). We will pass two arrays as a parameter and it will return the Einstein’s summation convention.

Syntax: numpy.einsum()

Parameter: Two arrays.

Return : It will return the Einstein’s summation convention.

Example 1:

Python

import numpy as np


array1 = np.array([1, 2, 3])
array2 = np.array([4, 5, 6])

# Original 1-d arrays
print(array1)
print(array2)
r = np.einsum("n,n", a, b)

# Einstein’s summation convention of
# the said arrays
print(r)

Output:

[1 2 3]
[4 5 6]
32

Example 2:

Python

import numpy as np


ar1 = np.arange(9).reshape(3, 3)
ar2 = np.arange(10, 19).reshape(3, 3)

# Original Higher dimension
print(ar1)

print(ar2)
print("")
r = np.einsum("mk,kn", ar1, ar2)

# Einstein’s summation convention of
# the said arrays
print(r)

 Output:

[[0 1 2]
 [3 4 5]
 [6 7 8]]
[[10 11 12]
 [13 14 15]
 [16 17 18]]

[[ 45  48  51]
 [162 174 186]
 [279 300 321]]