Could not evaluate "aSubExpr" error.

Hello!

I am trying to simulate a photoacoustic system in your program (now including a driving force in the form of a simulated laser). The thermoacoustic equations I coupled all seem to potentially work, but the laser heating term I'm using doesn't seem to work, no matter what I do. The equation I'm using is as follows (not a PDE, but perhaps I can formulate it as one):

H = I/(pi*w^2)*exp((-y^2+z^2)/(2w^2))

This is a standard equation for heating by a Gaussian laser. The error I get when trying to solve is as follows:
Could not evaluate the expression "-(aSubExpr(:,1))./(pi.*(0.001).^2).*exp(-aSubExpr(:,2).^2./(2w.^2)-aSubExpr(:,3).^2./(2w.^2))+aSubExpr(:,4)".

My question is, why do some of the constants I put in show up in the error, and others just show up as aSubExpr(:,#)? Sometimes the actual variable I use shows up too, and not the value. Could you please explain this or reference me to somewhere in the documentation I can learn more about it?

Not quite sure, if your approach is viable since it is not a PDE, but the divisor "/(2w^2)" is not valid without writing the multiplication explicitly.