% function output = bs_lorenz_rhs(t,x)
%   Compute right hand side (rhs) term of the Lorenz System
%   dX/dt = -aX   +aY
%   dY/dt = +rX   -Y       -XZ
%   dZ/dt =           -bZ  +XY
%
function output = bs_lorenz_rhs(t,x)
% model parameters
a=10.;  r=28.;    b=8./3.;
X=x(1); Y=x(2); Z=x(3);

% compute right hand side of differential equation
rhsX = - a*X + a*Y               ;
rhsY = + r*X -   Y         - X*Z ;
rhsZ =              - b*Z  + X*Y ;

% assign rhs to output variable
output = zeros(3,1);
output(1)=rhsX;
output(2)=rhsY;
output(3)=rhsZ;

% Alternatively one could have done this to shorten the code. 
% output = [a*(x(2)-x(1)), x(1)*(r - x(3)) - x(2), x(1)*x(2) - b*x(3)]';