Specifying Runtime of Multiple Particle Releases

[adeleanderson]

I'm new-ish to Python and would be grateful for anyone's input on my question.

I have 18 years of velocity data. I wrote a program that releases particles from the same location every 5 days for all 18 years using this very helpful Delay Start Tutorial (I utilized the "repeatdt" method).

However, I really only need each release of particles to run for 1 year (although I would like particles to continue being released every 5 days for all 18 years). The tutorial clearly describes how to STOP delay start releases (using pset.repeatdt= None) and then continue running the existing particles for a specified duration, but I'm seeking how to terminate my delayed-start particles after a given time while still allowing new delayed releases for all 18 years, all of which should have a runtime of 1 year.

Thank you for any ideas or suggestions you might have!

[erikvansebille]

Hi @adeleanderson. The easiest solution to stop a particle is to keep track of its 'age' and either delete it or stop it when it has reached a certain age. This can be done with a constant, particle class and kernel like the one below

fieldset.add_constant('maxage', 365.*86400)

class AgingParticle(JITParticle):
    age = Variable('age', dtype=np.float32, initial=0.)

def Age(particle, fieldset, time, dt):
    particle.age = particle.age + math.fabs(dt)
    if particle.age > fieldset.maxage:
        particle.delete()

[adeleanderson]

Hi @erikvansebille. Thank you so much for this response! I've successfully implemented the suggestion you wrote and the runtime of my code is now significantly shorter. I appreciate it!