If you use Automatic cycles, OS will keep optimizing until the difference in merit function betwen cycles is something like 10^-8 of the starting value. So it's not the variables, its the MF that controls the number of cycles.

Your best best is to just run 5 cycles or some number rather than using Automatic.

OS uses double precision floats for all variables.

- Mark

Thanks Sir, 

   As you said OS uses double precision floats for all variables. 

  But from Google search I found that smallest double precision floats number is ±10^(-323) [Please correct me if I am wrong].

Isnt it a very small change in variables to find next minimum merit function?

[One question also in my mind is that why OpticStudio uses floats as provided from OS.. instead cant it be use floats limit as per own requirement]

In other words, I strongly recommend OpticStudio Scientists and Engineers to add a feature where we choose decimal places upto

which Zemax allowed vary the variables to find next best merit function during the optimization, not finer than this limit. 

I guess its more efficient way of using the processing time.

 Please clarify.. Thanks Mark..

Regards 

Hi Satheesha,

I'm pretty sure that there is a difference between the smallest number a chip can represent and the smallest difference between numbers that it can work on. In other words, if that 10^-323 is used with much larger magnitude numbers for math purposes, it will be rounded out entirely. 

But what Mark said is the essential lesson for the optimization. Typically a double precision number is around 16 decimal places, but the optimizer goes to about 8. It does not try for higher precision. And more importantly, it is the merit function that is calculated to this precision, not the value of any given variable. One of the reasons for having different weights on operands is to account for some of them returning values of drastically different magnitudes and trying to compare them. I'm not a Zemax developer so I can only make reasonable guesses here, but the optimization routines are based on continuous mathematical functions, so trying to impose a discreteness to the internal calculations, like the step sizes for physical quantities, might be a more complicated matter than we realize.

The best way to approach granular values in the LDE is to optimize and then set the values in the LDE to the desired precision. This is what we would do prior to tolerancing, for example. 

For radii, I would suggest running the test plate fitting tool, even if you are not using that manufacturer (but especially if so). This will set all radii to sensible values taken froma  manufactuere's tooling list. For thicknesses, when you run the design lockdown tool you can specify the precision of the thickness values.

Optimization is a continuous process, but manufacture is not so it's best to keep an optimize-versus-tolerancing mindset here.

- Mark

Hi Mark Sir and Kevin, 

Thanks very much for your responses..  However  I will go through once with Zemax Help manaul about the details of Optimzation process, then I will come back to you.

Thanks 

--Satheesha.