What is the difference between unifrnd and rand?

Since both unifrnd() and rand() generates random variables from a continuous uniform distribution, I wonder if there is any difference in terms of their usage and sampling accuracy etc., or the difference would just be the fact that unifrnd allows direct specification of the bounds of the uniform random variable.

Thanks!

Answer 1

[Fei Deng]

Hello Natacha,

the function unifrnd actually calls rand. If a and b are the two first arguments of unifrnd, and r is the output of unifrnd, what unifrnd does is:

a2 = a/2;
b2 = b/2;
mu = a2+b2;
sig = b2-a2;

r = mu + sig .* (2*rand(sizeOut,'like',mu)-1);

Of course there are some error checks as well.

Type the following command in the MATLAB command window to take a look of the code: >>edit unifrnd

Of course they are few other differences in terms of usage (syntax). You can find more information from help documentation. https://www.mathworks.com/help/stats/unifrnd.html?searchHighlight=unifrnd&s_tid=doc_srchtitle https://www.mathworks.com/help/matlab/ref/rand.html?searchHighlight=rand&s_tid=doc_srchtitle

Another difference is that unifrnd is accessible when you have installed Statistics and Machine Learning Toolbox.