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Compute Dot Product using np.dot and custom ufunc in NumPy

NumPy: Universal Functions Exercise-12 with Solution

Vectorized Operations with ufuncs:

Write a NumPy program that creates two 1D arrays and uses np.dot to compute the dot product. Verify the result using a custom ufunc.

Sample Solution:

Python Code:

import numpy as np

# Create two 1D NumPy arrays
array_1 = np.array([1, 2, 3])
array_2 = np.array([4, 5, 6])

# Compute the dot product using np.dot
dot_product = np.dot(array_1, array_2)

# Define a custom ufunc to compute the dot product
def custom_dot(x, y):
    return np.sum(np.multiply(x, y))

# Create a ufunc from the custom function using np.frompyfunc
custom_dot_ufunc = np.frompyfunc(custom_dot, 2, 1)

# Verify the dot product using the custom ufunc
verified_dot_product = custom_dot_ufunc(array_1, array_2)

# Print the original arrays, the np.dot result, and the verified result
print('Array 1:', array_1)
print('Array 2:', array_2)
print('Dot product using np.dot:', dot_product)
print('Dot product using custom ufunc:', verified_dot_product)

Output:

Array 1: [1 2 3]
Array 2: [4 5 6]
Dot product using np.dot: 32
Dot product using custom ufunc: [4 10 18]

Explanation:

  • Import Libraries:
    • Imported numpy as "np" for array creation and manipulation.
  • Create Two 1D NumPy Arrays:
    • Created two 1D NumPy arrays named ‘array_1’ with values [1, 2, 3] and array_2 with values [4, 5, 6].
  • Compute Dot Product with np.dot:
    • Used the np.dot function to compute the dot product of 'array_1' and 'array_2'.
  • Define Custom Function:
    • Define a custom function custom_dot that takes two inputs x and y, computes their element-wise multiplication, and returns the sum of the results.
  • Create ufunc from Custom Function:
    • Create a ufunc from the custom function using "np.frompyfunc". The function takes the custom function, the number of input arguments (2), and the number of output arguments (1).
  • Verify Dot Product with Custom ufunc:
    • Used the custom ufunc ‘custom_dot_ufunc’ to verify the dot product of 'array_1' and 'array_2'.
  • Finally print the original arrays, the result from np.dot, and the verified result from the custom ufunc.

Python-Numpy Code Editor: