Question

Write a program in python to add subtract and multiply two matrices. These matrices can be of any greed such as 2 × 2 or 2 × 3 or 3 × 3 or 3 × 2 etc.

I am giving 36 points and expecting good answer.​

Answer 1

Solution.

The given co‎‎de is written in Python.

import numpy as np

def displayMatrix(a):

   for i in a:

       print('  '.join(str(x) for x in i))

def inputMatrix(rows,cols):

   A=[]

   for i in range(rows):

       X=[]

       for j in range(cols):

           X.append(eval(input('>>')))

       A.append(X)

   return A

a=int(input('Enter the number of rows for the first matrix: '))

b=int(input('Enter the number of cols for the first matrix: '))

print('Enter the matrix items..')

A=inputMatrix(a,b)

print('----------------------------------')

c=int(input('Enter the number of rows for the second matrix: '))

d=int(input('Enter the number of cols for the second matrix: '))

print('Enter the matrix items..')

B=inputMatrix(c,d)

print('----------------------------------')

print('1. Addition.')

print('2. Subtraction.')

print('3. Multiplication.')

choice=int(input('Enter your choice: '))

try:

   if choice==1:

       if a==c and b==d:

           C=np.add(A,B)

       else:

           raise Exception

       print('Sum of the matrix is:')

       displayMatrix(C)

   elif choice==2:

       if a==c and b==d:

           C=np.subtract(A,B)

       else:

           raise Exception

       print('Difference of the matrix is:')

       displayMatrix(C)

   elif choice==3:

       C=np.dot(A,B)

       print('Product of the matrix is:')

       displayMatrix(C)

   else:

       print('Invalid Choice.')

except:

   print('Sorry but the operation cannot be performed.')

Explanation.

• The problem is solved using numpy module. We have two matrices and we have to perform matrix addition, subtraction and multiplication.
• Numpy module has functions add(), subtract() and dot() which can be used to add subtract and multiply matrices. The displayMatrix() method is used to display 2d array in matrix form.