 input distribution
%        (viii) 'dCds' - derivative of inv(s)*(covariance of the input and the 
%                predicted control) wrt the variance of the input distribution
%        (ix)   'dCdp' - derivative of inv(s)*(covariance of the input and the 
%                predicted control) wrt the controller parameters
%   policy   policy structure
%     .fcn   function handle to policy
%     .<>    other fields that are passed on to the policy
%   m        mean of the input distribution
%   s        co