How to solve rms calculation problem ?

I have the following error:

Undefined function 'rms' for input a

rguments of type 'double'.

Answer 1

[Azzi Abdelmalek]

The rms function requires a signal processing toolbox

[Leonardo Wayne]

Thanks. It worked before though, so its a bit weird. I just solved it using: outrms = sqrt(mean(y.^2))