## Monday, August 9, 2010

### Creating Random Numbers in Matlab

Generating a matrix of random numbers:
The following code generates a 1 by 1000 matrix of 1000 random numbers between 0 and 1.

rand(1,1000);

Generating a Number between a and b
:
The following code generates a uniform whole random number between 1 (a) and 100 (b).

a = 1;
b = 100;
x = round(a + (b-a) * rand);

a and b can be adjusted as desired. For a normal Gaussian random number, the randn function can be used in place of rand above.

Here is the Matlab code for the plot above.

%% Generating random numbers in Matlab
% James Eastham
% Member, IEEE
% Revision: R1-0-0
clear all;
close all;
%% Generating 1000 random numbers using rand and randn
% This section generates a matrix of 1000
% random numbers between 0 and 1 using the
% rand and randn functions. The rand function
% creates a uniform distribution while the
% randn function generates a normal (Gaussian)
% distribution
x = rand(1,1000); %generates a 1 by 1000 matrix
figure('Color',[1 1 1]);
subplot(2,1,1);
hist(x);
title('1000 Random Numbers: Uniform');
x = randn(1,1000); %generates a 1 by 1000 matrix
subplot(2,1,2);
hist(x);
title('1000 Random Numbers: Gaussian/Random');
%% Generating a random number between 1 and 100
% The following code demonstrates a method
% for generating a random number between
% 1 (a) and 100 (b). The round function is
% used to round the number to the closest whole
% number.
a = 1;
b = 100;
x = round(a + (b-a) * rand)