How Many Rays Do I Need for Monte Carlo Optimization? 1*dN. v:5
While it is important to ensure that a sufficient number of rays are traced to 2*z~ 'i
distinguish the merit function value from the noise floor, it is often not necessary to 3,{eH6,O7M
trace as many rays during optimization as you might to obtain a given level of O=RS</01!
accuracy for analysis purposes. What matters during optimization is that the j _N<aX
changes the optimizer makes to the model affect the merit function in the same way I@/
G#3Zr
that the overall performance is affected. It is possible to define the merit function so pQ:^ ziwa3
that it has less accuracy and/or coarser mesh resolution than meshes used for qfE0J;e
analysis and yet produce improvements during optimization, especially in the early /[FDiJH2
stages of a design. i:0 v6d
A rule of thumb for the first Monte Carlo run on a system is to have an average of at fP|[4 ku
least 40 rays per receiver data mesh bin. Thus, for 20 bins, you would need 800 rays )c' 45 bD
on the receiver to achieve uniform distribution. It is likely that you will need to nco .j:
define more rays than 800 in a simulation in order to get 800 rays on the receiver. wPjq
B{!Q
When using simplified meshes as merit functions, you should check the before and S i?s69
after performance of a design to verify that the changes correlate to the changes of bN zb#P#hP
the merit function during optimization. As a design reaches its final performance bkD VW
level, you will have to add rays to the simulation to reduce the noise floor so that v4"Ukv
sufficient accuracy and mesh resolution are available for the optimizer to find the m] >zdP+
best solution.
