## What is the difference between rand and copularand

### SOUVIK DATTA (view profile)

on 19 Jul 2019
Latest activity Edited by the cyclist

on 21 Jul 2019

### the cyclist (view profile)

What is the difference between rand and copularand?
When I am going to apply copulacdf on some data, do I need to feed the rank transformation of the given data(rank CDF) or data transformed by copularand (like for every different copulacdf (gaussian or gumbel or frank etc.), we need to transform data accrodingly )?
what is the application of copularand? where to use the copularand transformation as input?
thank you.

R2019a

### the cyclist (view profile)

on 19 Jul 2019
Edited by the cyclist

### the cyclist (view profile)

on 20 Jul 2019

It's a little difficult to know where to start with an explanation? Do you know what a copula is, and why it is used? If not, maybe start by reading this wikipedia article.
I guess I would say that the main difference between rand and copularnd is that rand is for generating random numbers in one variable from a uniform distribution, and copularnd is for generating multiple variables, related by the copula.
See the following code, which is a slight variation on the example from the documentation for copularnd.
rng default % For reproducibility
tau = -0.8;
rho = copulaparam('Gaussian',tau);
u = copularnd('gaussian',rho,1000);
figure
scatterhist(u(:,1),u(:,2))

SOUVIK DATTA

### SOUVIK DATTA (view profile)

on 20 Jul 2019
Sir,
Thank you for your reply. All I need to know if I want to calculate cpolacdf for some random variables, whichone (rand or copularnd) is to use?
the cyclist

on 21 Jul 2019