"Maximum variable size allowed by the program is exceeded." When using the syndtable command

I've been working on some Hamming codes recently. Then I got my H matrix which is a 64x72 matrix and i want to make a decoding table (syndrome table) using the command "syndtable(H)"

every time i do that command i get the error:

t = syndtable(H4) ??? Error using ==> zeros Maximum variable size allowed by the program is exceeded.

Error in ==> syndtable at 28 table = zeros(2^n_k,n);

Anyone know what am I doing wrong ?

[Roger Stafford]

What is are the values of n_k and n? It is easy to make 2^n_k of astronomical size for large n_k.

Answer 1

[Friedrich]

Hi,

n_k is 64 so

>>2^n_k

ans =

     1.8447e+19

and n is 72. The code calls zeros(2^n_k,n) which would requiere a total amount of elements:

>> (2^n_k)*n

ans =

     1.3282e+21

However the maximum amount of elements in any array/matrix is:

[~,max_elements] = computer

max_elements =

     2.8147e+14

which is lower than the amount you requested. So you get the error you are facing.

In addition, if that limit wouldn't exist you would need a huge amount of memory in order to store that double matrix:

   >>(1.3282e+21)*8/1024^4

ans =

     9.6639e+09

So 9.6e+09 TB of memory.