function K = phicoeff(A,p0)
[m,m,t] = size(A);
n = t+1;

dims = repmat([m],[1 n]);

K = zeros(m^n,1);

for xind=1:m^n
  x = ind2coord(xind,dims);
  if x(1)==1
    K(xind) = (1-p0(1))*ptil(A,x);
  else
    K(xind) = -p0(x(1))*ptil(A,x);
  end
end
return


function p = ptil(A,x)
p = 1;
for j=2:length(x)
  p = p * A(x(j),x(j-1),j-1);
end
return