Compound quaternion Matlab -error

Hi, I have written a Matlab code where i can compound two relative poses by Translation-Vecot-Unit-Quaternion-Pair

But I get an error and I did not know why. The error message is:

Output argument "t_q_pair_A_C" (and possibly others) not assigned a value in the execution with "test2>t_q_pair_compound"

function.

Error in test2 (line 40)

q_pair_A_C = t_q_pair_compound(t_q_pair_A_B,t_q_pair_B_C);

Can anybody give me a hint why I get this error message. Thank you :)

Here is my code:

.

Answer 1

[KSSV]

In this function:

function t_q_pair_A_C = t_q_pair_compound(t_q_pair_A_B,t_q_pair_B_C)

% Extract Translation Vectors
t_A_B = t_q_pair_A_B.t;
t_B_C = t_q_pair_B_C.t;

% Extract Unit Quaternion
q_A_B = t_q_pair_A_B.q;
q_B_C = t_q_pair_B_C.q;

%Compound Translation Vectors
t_A_C_pure_q = q_pure(t_A_B) + q_A_B * q_pure(t_B_C) * q_inv(q_A_B);

[~, v_1,v_2, v_3] = parts(t_A_C_pure_q);
t_A_C = [v_1;
    v_2;
    v_3];

end

You need to assign the output. May be you want:

function t_q_pair_A_C = t_q_pair_compound(t_q_pair_A_B,t_q_pair_B_C)

% Extract Translation Vectors
t_A_B = t_q_pair_A_B.t;
t_B_C = t_q_pair_B_C.t;

% Extract Unit Quaternion
q_A_B = t_q_pair_A_B.q;
q_B_C = t_q_pair_B_C.q;

%Compound Translation Vectors
t_A_C_pure_q = q_pure(t_A_B) + q_A_B * q_pure(t_B_C) * q_inv(q_A_B);

[~, v_1,v_2, v_3] = parts(t_A_C_pure_q);
t_q_pair_A_C = [v_1;
    v_2;
    v_3];

end

[Mark S]

Thank you very much now it works :)

[KSSV]

Thanks is accepting/ voting the answer. :)

[KSSV]

You are using a different variable name for that. This line:

q_pair_A_C = t_q_pair_compound(t_q_pair_A_B,t_q_pair_B_C);

should be:

t_q_pair_A_C = t_q_pair_compound(t_q_pair_A_B,t_q_pair_B_C);