I tried to use mathmatical expression to define a pencil beam with lateral cross section of 1 mm^2. I used annular beam with Rmax with the expression sqrt(0.01/pi), but the running finishes with mistakes without any output. However, if I change this value to a number, e.g., 0.05642, the calcualtion can run without problem.
Will anyone please help me figure out what the problem is？
I think I found the problem, the space in a what cannot hold the lenght of sqrt(0.01/pi) but there’s no warning for this problem so the parameter tranfer to the calculation is failed. Usting the #define solved this problem.