function a=softmax(EstQ,tau)
% FUNCTION a=softmax(EstQ, tau)
%     Input: Estimated payoff values in EstQ (size 1 x N,
%            where N is the number of machines
%            tau - "temperature": High values- the probs are all
%            close to equal; Low values, becomes "greedy"
%     Output: The machine that we should play (a number between 1 and N)

% A little error checking first-  See that tau has a value.
if tau==0
  fprintf('Error in the SoftMax program-\n');
  fprintf('Tau must be greater than zero\n');
  a=0;
  return
end

%Compute the probabilities using the softmax computation.
Temp=exp(EstQ./tau);
S1=sum(Temp);
Probs=Temp./S1; %These are the probabilities we’ll use

%Select machine "a" using probability Probs(a) we just computed.
x=rand;
TotalBins=histc(x,[0,cumsum(Probs)']);
a=find(TotalBins==1);