Regarding usr1 subroutine

Just a general query of sorts…
Usr1 is something that is called once every timestep. There is another one called usr2.f which is called every iteration. Say I were to set a boundary condition which varies spatially (along that boundary) but not temporally, would that mean that this (USR1) BC is imposed at the beginning of the timestep but changes in between the iterations?

If it doesn’t vary in time, then you could set it up in usr0.f which is called before the time loop.

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But keeping it for every time step, although it doesn’t change temporally, should not make any difference either, correct?

I believe that is correct, try it and see!

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