Error using hist function for entropy calculation

Hi,

I am currently trying to write a function to calculate the Shannon entropy of some data, however, am getting the following error:

Requested 10000000001x1 (74.5GB) array exceeds maximum array size preference. Creation of arrays greater than this limit may take a long time and cause MATLAB to become unresponsive. See array size limit or preference panel for more information. Error in linspace (line 33) y = d1 + (0:n1).*(d2 - d1)./n1; Error in hist (line 96) edges = linspace(miny,maxy,x+1);||||_

The code I have currently is as follows:

 N = 1000;
 D = 10;
 Nbinsizes = 5;

 % create a random white noise signal
 x = randn( 1, N);

 nbins = logspace( 10, Nbinsizes, N / 10);
 Histogram_Shannon_Entropy = nan( 1, Nbinsizes);
 for i = 1:Nbinsizes
     p = hist( x, nbins( i))/N;
     Histogram_Shannon_Entropy( i) = sum( -( p( p > 0) .* ( log2( p ( p > 0)))));
 end

I'm struggling to understand what the cause of this error is, so any help is greatly appreciated! Thank you kindly in advance.

Answer 1

[Walter Roberson]

You have

   nbins = logspace( 10, Nbinsizes, N / 10);

logspace(A, B, N) is equivalent to

10.^linspace(A, B, N)

so you are asking for 10.^(10, 5, 100)

The first entry of that is going to be 10^10 . And you are asking for that to be used as the number of bins in your hist() call.

[Dhani Dharmaprani]

Thank you so much for that, that makes sense!