Problem with large array

[George]

Hi,

I am creating a large matrix, and got the following error: 

error: memory exhausted or requested size too large for range of Octave's index type -- trying to return to prompt.

The size of the matrix when the error occurs is 23,289 x 2,387 or about 55,000,000 elements.

Working in WIndows XP, on Octave 3.2.4. I have a 64 bit CPU, but I think running Windows 32 bit version.

I am combining the elements of two matrices. Here is the code:

  X_big = [];

  Y_big = [];

  nm = size(R, 1);

  np = size(R, 2);

  for m_counter = 1 : nm

    printf("%i...", m_counter);

    for p_counter = 1 : np

      if R(m_counter, p_counter) == 1

        this_row = [features(m_counter, :), Y'(p_counter,:) ];

        X_big = [X_big; this_row];

        Y_big = [ Y_big; Y(m_counter, p_counter) ];

      endif

    endfor

  endfor

The final matrix should be approximately of size 34,000 x 2,387 or about 80,000,000 elements.

Can you please answer a few questions?

1. How can I fix this error?

2. This process is very slow...taking about 6 hours (if it finished.) Is there a better way to do this?

Thank you for your help.

George