Dot_and_Cross.md

Day #12 - Dot and Cross

Problem

dot

The dot tool returns the dot product of two arrays.

import numpy

A = numpy.array([ 1, 2 ])
B = numpy.array([ 3, 4 ])

print numpy.dot(A, B)       #Output : 11

cross

The cross tool returns the cross product of two arrays.

import numpy

A = numpy.array([ 1, 2 ])
B = numpy.array([ 3, 4 ])

print numpy.cross(A, B)     #Output : -2

Task

You are given two arrays A and B. Both have dimensions of N X N. Your task is to compute their matrix product.

Input Format

The first line contains the integer N. The next N lines contains N space separated integers of array A. The following N lines contains N space separated integers of array B.

Output Format

Print the matrix multiplication of A and B.

Sample Input

2
1 2
3 4
1 2
3 4

Sample Output

[[ 7 10]
 [15 22]]

Solution

import numpy as np
n= int(input())
a = np.array([input().split() for _ in range(n)],dtype=np.int)
b = np.array([input().split() for _ in range(n)],dtype=np.int)

res = []
for r in range(n):
    row = [np.dot(a[r,:],b[:,i]) for i in range(n)]
    res.append(row)

res = np.array(res)
print(res)