randintv.m

来自「ITU-T G.723.1 Speech Coder: Matlab imple」· M 代码 · 共 22 行

function [iR, Seed] = RandIntV (Seed, N)
% Generate a random integer in the interval [0, N-1].

% The original C-code for random number generation was as follows:
%   *p = (Word16)(((*p)*521L + 259) & 0x0000ffff)
% This code uses integer arithmetic: The seed (Word16) is promoted
% to long before being multiplied by 521. The result is masked to
% 16 bits.
%
% Here we work with unsigned integer values (in Matlab doubles).   

% $Id: RandIntV.m 1.5 2004/08/25 G.723.1-v2r1a $

if (N == 1)
  iR = 0;    % Don't invoke the random number generator
else
  Seed = mod (521 * Seed + 259, 65536);
  iR = fix (mod (Seed, 32768) * N / 32768);
end

return