a function for computing bursts of errors

[Francesco Potorti`]

Say I have a list of 1's and 0's, each 1 representing a rare event (an
error), each 0 representing a normal event (no error).  I want to
compute the distribution of error burst lengths.  This function makes an
array where each element, one per error burst, contains the burst
length.

Now that I discovered about bool values, is there a way that I could
take advantage of boolean arrays in this function?

===File /home/pot/math/octavelib/tsa/bursts.m===============
function b = bursts(x)

  ## usage: B = bursts (X)
  ##
  ## Given a matrix X, return the number of bursts of different lengths.
  ##
  ## A burst of length n is a sequence of n values different from 0,
  ## delimited either by zero values or the start or end of the vector.
  ##
  ## Francesco Potortì <address@hidden>, 2004
  ## License: GNU GPL <http://www.gnu.org/licenses/gpl.html>

  if (nargin != 1)
    usage ("B = bursts (X)");
  endif

  if (!isvector(x))
    error ("bursts: x must be a vector");
  endif

  ## Make x a column vector of ones where different from 0.
  if (columns(x) != 1)
    x = x';
  endif
  x = !x;

  ## Find the places where there is a 1, then compute the burst lenghts.
  b = diff([0;find(x);rows(x)+1])-1;

  ## Remove the zero-length bursts
  b = b(b>0);
endfunction
============================================================

-- 
Francesco Potortì (ricercatore)        Voice: +39 050 315 3058 (op.2111)
ISTI - Area della ricerca CNR          Fax:   +39 050 313 8091
via G. Moruzzi 1, I-56124 Pisa         Email: address@hidden
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