NumPy | Vector Multiplication

Vector multiplication is of three types:

• Scalar Product
• Dot Product
• Cross Product

Scalar Multiplication:
Scalar multiplication can be represented by multiplying a scalar quantity by all the elements in the vector matrix.








Code: Python code explaining Scalar Multiplication

# importing libraries
import numpy as np
import matplotlib.pyplot as plt
import math

v = np.array([4, 1])
w = 5 * v
print("w = ", w)

# Plot w
origin =[0], [0]
plt.grid()
plt.ticklabel_format(style ='sci', axis ='both',
                     scilimits =(0, 0))
plt.quiver(*origin, *w, scale = 10)
plt.show()

Output :

w =  [20  5]

Dot Product multiplication:

Code: Python code to explain Dot Product Multiplication

import numpy as np
import math

v = np.array([2, 1])
s = np.array([3, -2])
d = np.dot(v, s)
print(d)

Here, dot product can also be received using the ‘@’ operator.

d = v@s

Output :

4

Cross Product:

Code: Python code explaining Cross Product

import numpy as np
import math

v = np.array([4, 9, 12])
s = np.array([21, 32, 44])
r = np.cross(v, s)
print(r)

Output:

[ 12  76 -61]