MATLAB: Unable to use a value of type matlab.gra​phics.prim​itive.Line as an index. How do i fix this

Question

fodo=[ 1 1 2.5 0 ;

5 1 1.0 0 ;

1 1 1.5 0 ;

4 1 2.0 60;

1 1 1.5 0 ;

5 1 1.0 0 ;

1 1 2.5 0 ]

ring=repmat(fodo,6,1);

beamline=repmat(fodo,6,1)

dv=[0;0;beamline(line,3)]; dw=eye(3);

Unable to use a value of type matlab.graphics.primitive.Line as an index.

Answer 1

'line' is MATLAB's built-in function. You haven't defined it as something else in your code. Therefore, the statement

beamline(line,3)

causes error.