gallager_f.m

density evolution for LDPC codes design and some related documents

% gallager_f.m
function y = gallager_f(x)
if x < 0.00001
  y = 12.21; % 12.21=gallager_f(0.00001)
else
  y = log((exp(x)+1.0)/(exp(x)-1.0));
end;