Example 7 is not working correctly

[8bit-Dude]

I downloaded the library as I am interested in Fresnel lens design, and tried it in Matlab 2015a.
But unfortunately, example7 throws a number of errors in Rays.m
The matrix operations are somehow incorrect (line 474 and on-ward).
Any chance you could take a look?

[alexschultze]

The example performes just fine for me (on Matlab 2018b) for the current HEAD branch.

[8bit-Dude]

Alright, I fixed the issue myself:

Older versions of Matlab do not implicitly replicate matrices when their dimensions do not match. In my opinion, it is not really good practice to rely on Matlab replicating matrices for you... the behaviour is more than likely to change at some point in future (Mathworks don't care that much about backward compatibility).

I could run the code in Matlab 2015a with these small edits:

Rays.m, line 474:
dims = size(r_in);
rin = repmat([ surf.vx( i ) + surf.sag( i ), 0, 0 ],dims(1),1) + ...
conic_intersection( r_in - repmat([ surf.vx( i ) + surf.sag( i ), 0, 0 ],dims(1),1), e, ring );

quadric_intersection.m, line 64:
    dims = size(n);
    r1 = r0 + n .* repmat(t1,1,dims(2));
    r2 = r0 + n .* repmat(t2,1,dims(2));

Additionally, older version of Matlab do not support the syntax text( ax, ....). It is possible to fix draw_lens_engineering.m with a few edits like this:

    ax = gca(); axes(a1);
    text(-0.2 * R, sgn * 1.5 * Rm, 'A', 'FontSize', 30 ); 
    axes(ax);

If you could make these few changes, the Toolbox will work properly with version 2015, and maybe older...

[8bit-Dude]

Another minor issue: when switching condition to 'smooth' the ray simulation works but the call to draw_lens_engineering() fails (since it stipulates a 'Fresnel' lens).