FFT of a row of data (for a beginner)

Hello, I am an undergraduate student and I want to use the fft function to change a row of data points from the time domain to the frequency domain and then get the power spectrum. The row in question is a 1x600010 matrix of int16 type, taken from a 16x600010 int16 matrix. Right now my code is:

 limits = [1 600010];
 figure(1)
 x = (1:600010);
 y = double(Data(1,:))
 plot(x,y,'r');
 xlim(limits);

 fs = 1000;
 t = 0:1/fs:600010-1/fs;
 m = length(y);
 n = pow2(nextpow2(m));
 Y = fft(y,n);
 f = (0:n-1)*(fs/n);
 power = Y.*conj(Y)/n

 figure(2)
 plot(f,power)

MATLAB says that there is an error in this line: Y = fft(y,n) because 'fft' is an undefined function for input arguments of type 'int16'. How do I change the type of the matrix for it to be compatible with the code, if possible?

Answer 1

[Joseph Cheng]

convert the data using the function double()

 y = double(Data(1,:))

you can read up on the different types of numbers and changing of types here: http://www.mathworks.com/help/matlab/numeric-types.html.

[cosined]

Thank you Joseph!