I am running a code on autocorrelation in my MATLAB console but it is giving error. Can anyone point out the issue and how to fix it?

a = load('60lowfreehigh.lvm');
>> N = 50;
>> y = a;
>> z = a;
>> for i=1: N-1
for i=N-1:-1:1
a(i+1)=a(i);
end
x(1)=0;
a(1)=0;
z = [z;a];
end;
>> m=[z]*[y]';

The above code is returning the error;

Out of memory. Type HELP MEMORY for your options.

What is the problem and how can I fix it?

Thanks,

Anuradha

[Walter Roberson]

How big is the data in a ?