Add module to calculate near field and radiation field on user-define…

[HaoPengYY]

Add module to calculate electrical field on user-defined observation plane.

[PrometheusPi]

Hi @HaoPengYY,
thanks for providing an update to Clara2 via pull request. I will review it as soon as possible.
Could you briefly describe, how I can execute your code and what I should expect when testing.

[HaoPengYY]

@PrometheusPi Hi. Actually, I have performed the benchmarks described in Sec. 5.1 of your thesis, and I think they are enough to verify the feasibility of this module. I am now preparing a markdown to explain the code and the benchmarks. I don't know if I can put it here, or I can send it to you by email.

[PrometheusPi]

@HaoPengYY Cool you performed these benchmarks. I agree, they are perfectly suited for testing this module.
I would suggest that you upload the markdown file you are currently creating as a second commit to this pull request. (Just create a /doc directory in the clara2 git repo and put the file in there.) This would allow others to read your explanation as well.

Thanks a lot for your effort to provide this new module and its documentation. 👍

[HaoPengYY]

@PrometheusPi Hi. It is my first time to use git, I don't know if this is the right way. I put the markdown here as well.
Intro&BenchmarkToUOP.zip
Thanks to your code, I am now able to do a work I am interested in. But it will be a pain to run the code when a large number of trajectories are used as input files, maybe we are able to add them together before we dump the data files separately.

[PrometheusPi]

Dear @HaoPengYY,
I am very sorry that I had no time so far to look into your pull request. Hopefully there will be more time next week.
Please excuse the delayed review.

[PrometheusPi]

I am very sorry @HaoPengYY for not having the time yet to look into your pull request. I will hopefully be able to do so in September. Please excuse the delay. I hope it is fine for you to work on your branch.

[HaoPengYY]

@PrometheusPi Please don't be worry. The code now work fine for us, we have done some work based on the code. And also I have done some updates, like adding the module which calculates the far-field radiation field, changing the mpi logic (worker processors are assigned a new job after finishing the last job), adding all spectrum or electric fields coherently during calculation (no need for post-processing, save a lot of memory and facilitate simulations with a large number of trajectories). I would start a new pull request if everything is ready.