NumPy eye() function

The numpy.matlib.eye() function is used to return a matrix with all the diagonal elements initialized to 1 and with zero value elsewhere.

The numpy.matlib is a matrix library used to configure matrices instead of ndarray objects.

Syntax of matlib.eye():

The required syntax to use this function is as follows:

numpy.matlib.eye(n, m, k, dtype,order)   

Parameters:

Let us now cover the parameters used with this function:

• n
  This parameter is used to represent the number of rows in the resulting matrix.
• m
  This parameter is used to represent the number of columns and the default value is n.
• k
  This parameter is used to indicate an index of diagonal,value of this parameter is 0 by default if value of k>0 it means diagonal is above the main diagonal or vice versa.
• dtype
  This parameter is used to indicate the data type of the matrix. The default value of this parameter is float. This is an optional parameter.
• order
  This is an optional parameter that is used to indicate the insertion order of the matrix. It mainly indicates whether to store the result in C- or Fortran-contiguous order, The default value is ‘C’.

Returned Values:

This method will return a n x M matrix where all elements are equal to zero, except for the kth diagonal, whose values are equal to one.

Example 1:

Given below is a basic example for the understanding of this function:

import numpy as np  
import numpy.matlib  
  
x = numpy.matlib.eye(n = 4, M = 3, k = 0, dtype = int)
print("The Output is :")
print(x)

The Output is :
[[1 0 0]
[0 1 0]
[0 0 1]
[0 0 0]]

Example 2:

Let’s take another example, to create a matrix of different dimensions.

import numpy as np  
import numpy.matlib  
  
x = numpy.matlib.eye(n = 5, M = 4, k = 1, dtype = int)
print("The Output is :")
print(x)

The Output of the above code:

Difference between eye() and identity():

There is a difference between the Numpy identity() function and eye() function and that is, the identity function returns a square matrix having ones on the main diagonal like this:

while the eye() function returns a matrix having 1 on the diagonal and 0 elsewhere with respect to the value of K parameter, if value of K > 0 then it implies the diagonal above main diagonal and vice-versa.