% define roll, pitch and yaw variables
syms roll pitch yaw 'real'

% Define yransformaton matrices for rotations about the X,Y and Z body axes
Xrot = [1 0 0 ; 0 cos(roll) sin(roll) ; 0 -sin(roll) cos(roll)];
Yrot = [cos(pitch) 0 -sin(pitch) ; 0 1 0 ; sin(pitch) 0 cos(pitch)];
Zrot = [cos(yaw) sin(yaw) 0 ; -sin(yaw) cos(yaw) 0 ; 0 0 1];

% calculate the tranformation matrix from body to navigation frame resulting from
% a rotation in yaw, pitch, roll order
Tbn_321 = transpose(Xrot*Yrot*Zrot)

% convert to c code and save
ccode(Tbn_321,'file','Tbn_321.c');
fix_c_code('Tbn_321.c');

% define the quaternion elements
syms q0 q1 q2 q3 'real'

% calculate the tranformation matrix from body to navigation frame as a
% function of the quaternions
Tbn_quat = Quat2Tbn([q0;q1;q2;q3]);

% calculate the y,x terms required for calculation fo the yaw angle
yaw_input_321 = [Tbn_quat(2,1);Tbn_quat(1,1)];

% convert to c code and save
ccode(yaw_input_321,'file','yaw_input_321.c');
fix_c_code('yaw_input_321.c');