function mu = softmax(eta)
% Softmax function
% mu(i,c) = exp(eta(i,c))/sum_c' exp(eta(i,c'))
% This file is from matlabtools.googlecode.com
c = 3;
tmp = exp(c*eta);
denom = sum(tmp, 2);
mu = bsxfun(@rdivide, tmp, denom);
end