The OPAL Discussion Forum

[Daniel Winklehner <winklehn AT mit.edu>]

Hi All,

The information Anastasiya needs from the stat file is the z coordinate of 
the reference particle (seems like only s is given, which probably stems from 
the mismatch between OPAL-T and OPAL-cycl coordinate systems). Maybe we were 
looking in the wrong place, but if not it might warrant an additional column 
in the stat file rather than making this complicated through use of SYSTEM.

Cheers,
   Daniel

-----Original Message-----
From: opal-request AT lists.psi.ch <opal-request AT lists.psi.ch> On Behalf Of 
Anastasiya Bershanska
Sent: Thursday, June 28, 2018 4:59 PM
To: Jochem Snuverink <jochem.snuverink AT psi.ch>
Cc: Anastasiya Bershanska <nastya AT psfc.mit.edu>; opal AT lists.psi.ch
Subject: Re: [Opal] Multi objective optimization

Hello Jochem,

The calculation is not complicated and I can do math using built-in 
functions, but I need information from *-trackOrbit.dat. (I will have to use 
SYSTEM command.) How can I tell what is the correct output file for a 
specific run that is a part of optimization job?

Also, do you have an example of an optimization job that works? If not, can 
someone update the documentation to specify how such optimization should be 
setup? (i.e. is optimization command and the actual simulation setup are in 
one file or in two separate ones? what is the folder structure in case it’s 
two different files?)

Btw, runOPAL.py no longer recognizes —optPilot (at least when I tried). Could 
you please update/fix that on the wiki?

Thank you,
Anastasiya

> On Jun 28, 2018, at 4:59 AM, Jochem Snuverink <jochem.snuverink AT psi.ch> 
> wrote:
> 
> Hi Anastasiya,
> 
> Is the calculation of your variable very complicated? If not you can 
> calculate it perhaps in the input file directly? You have a few basic 
> functions available in the EXPR part (sqrt, pow, exp, log, fabs, sin, etc., 
> see https://gitlab.psi.ch/OPAL/Manual-2.0/wikis/optimiser) that you can use 
> on the stat file variables.
> 
> The general case is however not possible at the moment. If it is a 
> meaningful variable, we can possibly add it to the .stat file.
> 
> Alternatively, you can try to use the SYSTEM command 
> (https://gitlab.psi.ch/OPAL/Manual-2.0/wikis/control) at the end of each 
> run. This executes a system call, and if you do your calculation in a 
> separate program and write it to file, you can read in this file again with 
> "fromFile". This is untested, but I believe it should work.
> 
> hope this helps,
> Jochem
> 
> On 27/06/18 21:19, Anastasiya Bershanska wrote:
>> Hello,
>> 
>> I have a questions on the optimizer. According to the documentation, EXPR 
>> in OBJECTIVE and CONSTRAINT can be specified using a few built-in 
>> functions that take data from .stat file and variables defined in the 
>> temple file. However, I would like to be able to optimize with respect to 
>> a variable that I calculate using .stat and/or .dat files (i.e. specify 
>> OBJECTIVE as a new function of input files). Is it possible to specify an 
>> new function that reads from output files within OPAL input temple file?
>> 
>> Thank you,
>> Anastasiya
>