[ET Trac] [Einstein Toolkit] #487: SimFactory should allow steering of parameters between restarts

[Einstein Toolkit]

#487: SimFactory should allow steering of parameters between restarts
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  Reporter:  hinder       |       Owner:  eschnett
      Type:  enhancement  |      Status:  new     
  Priority:  major        |   Milestone:          
 Component:  SimFactory   |     Version:          
Resolution:               |    Keywords:          
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Comment (by bmundim):

 I should say that this is the main reason I haven't switched
 to SimFactory yet. I probably have already mentioned this
 before, but I should repeat here, that I commonly output
 a different number of variables between the initial data
 and evolution parts of the simulation. I find it useful for
 initial inspection (to see if everything is all right before
 spending thousands of SUs). It would be really great
 if SimFactory allows me to steer parameters so I don't
 need to hack into its internals to force a change
 of parameters.

 Also I can think of other examples where it could be useful:
 the case when you want to find the horizons with a different
 frequency in the inspiral phase than in the plunge and merger
 phases. Or if someone else has a very expensive analysis routine
 that would be turned on only at a particular time
 of the simulation (that we don't know when to do so in advance
 for a new simulation). Another example: your simulation quits with
 nans and you find out that you can avoid that by decreasing the
 courant factor or maybe by enlarging an AH mask in a hydro simulation,
 it would be very useful to still do so easily with SimFactory.
 Currently I don't think it is possible without hacking it. Since
 the other alternative, running my own scripts, gives me more freedom,
 I find it hard to justify all the time necessary to learn yet another
 tool (that may not give me such a freedom). Erik's ideal of a simulation
 unfortunately is currently too unrealistic, since all these eventual
 tweaks in the parameters would need to be some how dealt with
 automatically. I don't think that's possible.

 So, said that, maybe we can still use the same simulation infrastructure
 and if we need to change the parameter file for some reason, that would
 be stored in the appropriate checkpoint directory and tagged accordingly.
 This way the simulation is still easily reproducible by someone else.
 What do you think?

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Ticket URL: <https://trac.einsteintoolkit.org/ticket/487#comment:3>
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