Time tracking, delays?

[mamintatarin]

Hello!

I'm trying to use pvtrace for waveshifting fiber simulation. It actually re-emits light with some decay over the time, not only shifts the wavelength. I get that it is possible to calculate time since generation via speed of light and path history, and even add delays manually by analysing certain events in history, but pvtrace is not actually designed for time tracking - am I right?

[mamintatarin]

by the way, I figured out that I can do two things simultaneously by adding callable arguement to photon tracer:

1. Time tracking. Imagine that I pass a callable that receives enough information at each step and writes time since the start of simulation using refractive index of current volume & speed of light. I can write time directly into some new variable of each ray object as python allows to create variables without defining them

2. Dynamic tracing. In my case, I do not need all the paths, only those who reached certain volume with some conditions. So I can drastically reduce computation time by dropping or cutting paths at computation stage, rather than analysing them at post-processing.

All of this could be achieved by adding a user-defined optional callable with fixed signature to the photon tracer, without violating backward compatibility.

Is it worth making pull request?

[danieljfarrell]

Hi ,

Sorry I missed this! That's a really cool application, I wish I did more time-domain work when I was doing this.

Now, there is definitely a branch somewhere with this implemented already.

I cannot remember exactly how I did it, but I think because the tracer knows at all times the reactive index and the distance travelled it is a calculated variable.

If you wanted to offset rays from each other, to give them a particular creation time, then adding an attribute to the ray would make sense.

Put together a pull request if you want, would be good to see what you mean, even at a high level, it does not need to work yet.

[danieljfarrell]

Think I found it

b66dc4c

This is a notebook that demonstrates time resolved tracing. It's on a fairly old branch.

I added a radiative and non-radiative lifetime to Luminophore. From these we calculate the delay in emission, and also the quantum efficiency.

Might not be exactly what you need but feel free to hack away and let me know how it goes

[mamintatarin]

Thanks! I somehow resolved it for my personal task, but I hope I'll find some time to learn how you did it in this branch and probably implementing the feature in some way (if it needs updating code or smth) and make some new PR

[mamintatarin]

@danieljfarrell I made a pull request for this issue. May be I need to add some example notebooks? Looks like a good feature. By the way, added callable arg that stops tracing when reaching certain user-defined condition: it helps to reduce unnecessary calculations