Question

1. What does the following code compute? Explain what operation the third line is per- forming b = zeros(m, 1); for i = 1:m b(i) = A(i,:) * x; end Make a copy of the relevant MATLAB function you wrote earlier, and use this code in place of the two loops you wrote. Time both codes on a sufficiently large problem. Which performs faster?

Using MATLAB please.

A = rand(m,n)

x = rand(n,1)

b = A * x

Answer 1

`Hey,

Note: If you have any queries related to the answer please do comment. I would be very happy to resolve all your queries.

a)

Third line is basically assigning value at index i in b vector to the value ith row of A multiplied by column vector x

b)

clc

clear all

close all

format long

m=3;

n=4;

A = rand(m,n);

x = rand(n,1);

tic;

b = A * x

disp('time required for code in last program')

t1=toc

tic;

b=zeros(m,1);

for i=1:m

b(i)=A(i,:)*x;

end

disp('time required for code given in question')

t2=toc

4 5 6 7 - 8 - 9 10 11 12 13 - 14 - 15 - 16 17 18 19 - 20 format long m=3; n=4; A = rand(m, n); x = rand(n,1); tic; b = A * X disp('time required for code in last program') t1=toc tic; b=zeros(m, 1); for i=1:m b(i)=A(i, :)**; end disp('time required for code given in question') t2=toc Command Window New to MATLAB? See resources for Getting Started. time required for code in last program t1 = 0.001922745000000 time required for code given in question t2 = 0.004099275000000

Kindly revert for any queries

Thanks.