function[r,dr_dz] = rfunc(zSS,pstar)
%
%   Compute derivatives for return function of the 
%           Hansen model
%
%
nz = length(zSS);
lambda=zSS(2); kss=zSS(3); iss=zSS(4); hss=zSS(5); 


theta = pstar(1,1); 
delta = pstar(2,1);  
beta  = pstar(3,1);   
A     = pstar(4,1);
rho   = pstar(5,1);   
%
%
%
css = lambda*kss^theta*hss^(1-theta) - iss;
r   = log(css) + A*log(1-hss);
%
%    first derivatives
%
dr_dz = zeros(nz,1);
dr_dz(1,1) = 0;
dr_dz(2,1) = ((kss^theta)*(hss^(1-theta)))/css;
dr_dz(3,1) = (theta*lambda*kss^(theta-1)*hss^(1-theta))/css;
dr_dz(4,1) = -1/css;
dr_dz(5,1) = ((1-theta)*lambda*kss^(theta)*hss^(-theta))/css - A/(1-hss);