Peak to Peak Distance Help

So I have a large data set of monthly averages which came in as a vector of 5000 or so points. I converted into 12x235 a matrix and then averaged each column to give me a vector of yearly averages for the data. The data resembles a sin curve and I need to find the distance between each peak. When I tried to use the peak to peak function, [pks,locs]=findpeaks(data,'minpeakdistance',3), it told me it could not compute it for type double. I tried converting to int and no luck. Please help.

[Image Analyst]

What does:

>> which -all findpeaks

say in the command window? What happens if you say "doc findpeaks"?

[Image Analyst]

Are you sure it says it "could not compute it for type double", or does it really say "

Error using findpeaks (line 43)
Input arguments must be 'double'.

"? Because that's the complete opposite of what you said.

[Jake Larson]

 [pks,locs]=findpeaks(x,'minpeakdistance',3)

Undefined function 'findpeaks' for input arguments of type 'double'.

I have no clue why it won't work for type double?

Answer 1

[Leandro]

The findpeaks needs data to be a double variable, not ints.

data=double(data)

[pks,locs]=findpeaks(data,'minpeakdistance',3)

[Jake Larson]

I have it in doubles. This is the error i get

 Undefined function 'findpeaks' for input arguments of type 'double'.

Answer 2

[Greg Dionne]

It looks like you don't have the Signal Processing Toolbox.

You get that error when you try accessing a function that doesn't exist.

Try:

>> [pks,locs]=completelyundefinedfunction(x,'minpeakdistance',3) Undefined function 'completelyundefinedfunction' for input arguments of type 'double'.