rand

Purpose

Uniformly distributed random numbers and matrices.

Y = rand(n)
Y = rand(m,n)
Y = rand(size(A))
rand('seed')
rand('seed',n) 
rand

rand generates random numbers and matrices whose elements are uniformly distributed in the interval (0,1).

rand(n) is an n-by-n matrix with random entries.

rand(m,n) is an m-by-n matrix with random entries.

rand(size(A)) is the same size as A and has random entries.

rand('seed') returns the current value of the seed used by the generator.

rand('seed',n) sets the seed to n. rand('seed',0) sets the seed to its startup value.

rand with no arguments is a scalar whose value changes each time it is referenced.

The functions rand and randn maintain separate generators with separate seeds.

If rand has not yet been used during a particular MATLAB session, then R = rand(3,4) produces

 R =
    0.2190    0.6793    0.5194    0.0535
    0.0470    0.9347    0.8310    0.5297
    0.6789    0.3835    0.0346    0.6711

A random choice between two equally probable alternatives can be made with

 if rand < .5
    'heads'
 else
    'tails'
 end

rand is a uniform random number generator based on the linear congruential method described in [1]. The basic algorithm is

[1]Park, S.K. and K.W. Miller, "Random Number Generators: Good ones are hard to find," Comm. A.C.M., vol. 31, n. 10, pgs. 1192-1201, Oct. 1988.