Simulink error: Attempt to access an element that was not defined before use

Hello,

I have the following code in a Matlab function block in simulink:

 function D0 = ComputeD0(q)
 n=2;

 base_att=q(1:3);
 theta=q(4:n+1);
 m_DEM=zeros(1,n+1);
 vc=cell(1,n+1);
 wi=cell(1,n+1);
 Rot_0=cell(1,n+1);
 I_DEM=cell(1,n+1);

 coder.extrinsic('DEM_Dmatrix')

 [m_DEM,vc,wi,Rot_0,I_DEM]=DEM_Dmatrix(theta,base_att);

 % Matrix D
 d=cell(1,n+1);

 for i=1:n+1
 d{i}=m_DEM(i)*vc{i}*vc{i}.'+wi{i}.'*Rot_0{1,i}*I_DEM{i}*Rot_0{1,i}.'*wi{i};
 end

 dd=cell(1,n+1);
 dd{1}=d{1};
 for i=2:n+1
    dd{i}=d{i-1}+d{i};
    if i==n+1
        D0=dd{i};
    end
 end

When i run it i have the following error :

 Attempt to access an element that was not defined before use.

 Function 'D0 ' (#91.301.306), line 19, column 19:
 "vc{i}"

Does anybody have an idea what it means? Thank you :)

[Sudarshan Kolar]

Can you share the contents of DEM_Dmatrix?

You can put a breakpoint at the line:

   [m_DEM,vc,wi,Rot_0,I_DEM]=DEM_Dmatrix(theta,base_att);

And step your code from there to see the contents of 'vc'. This doc talks about debugging your MATLAB code.