Autocorrelation with big data

I have written this code to find autocorrlation

temp = xlsread('temp.xlsx');
tempnorm = temp - mean(temp);
fs = 2*24;   % 2 times per hours
t = (0:length(tempnorm)-1)/fs;
plot(t, tempnorm); xlabel 'Time in days'; ylabel 'Temp'; axis tight 
[autocor, lags] = xcorr(tempnorm, 3*7*fs, 'coeff');
plot(lags/fs, autocorr);

when i try to run this it shows

Index exceeds the number of
array elements (0).

Error in autocorr (line 143)
    y = args{1};

please help me to figure it out

Answer 1

[Sulaymon Eshkabilov]

One typo that caused the error:

plot(lags/fs, autocor);  % autocor is the variable name NOT autocorr

[Abdur Rob]

thank you

[Sulaymon Eshkabilov]

Most welcome!