Adding new limiters?

[donnaaboise]

Are there any thoughts about how to best add a new limiter? I am thinking of a case in which the user adds a new limiter to inline limiter.f90. There doesn't seem to be any way to indicate to the Python routines that they should accept a new limiter number. One idea is to allow a 'user' option + a number, i.e. The number would then indicate the goto location in the limiter file (or at least an offset from limiters known to Clawpack). The user is responsible for making sure this limiter gets called correctly (since they are supplying new limiter file).

[mjberger]

What brought this up? Do you want to add a new limiter yourself or know somebody who does? How interesting. — Marsha

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On Apr 4, 2019, at 5:40 AM, Donna Calhoun ***@***.***> wrote: Are there any thoughts about how to best add a new limiter? I am thinking of a case in which the user adds a new limiter to inline limiter.f90. There doesn't seem to be any way to indicate to the Python routines that they should accept a new limiter number. One idea is to allow a 'user' option + a number, i.e. The number would then indicate the goto location in the limiter file (or at least an offset from limiters known to Clawpack). The user is responsible for making sure this limiter gets called correctly (since they are supplying new limiter file). — You are receiving this because you are subscribed to this thread. Reply to this email directly, view it on GitHub <#239>, or mute the thread <https://github.com/notifications/unsubscribe-auth/AA1DC7wxt0bMriwDfJo63P_CT6sMotYqks5vdciagaJpZM4ccXCr>.

[mandli]

If you want to just test a limiter you could use PyClaw which has a number of additional limiters and would be trivial to add a new one. Otherwise in clawutil/src/python/clawutil/data.py starting at line 733 you could add another limiter option along with the associated code for the limiter in Fortran.

[donnaaboise]

Yes, I'd like to try out a new limiter. I am comparing results with Basilisk, and they use the generalized minmod limiter. I am not necessarily proposing to add it to Clawpack, though, and so haven't opted to edit data.py (as per suggestion by @mandli). In the same way we include a user option for boundary conditions, I just thought it would be useful to have a user option for limiters. Right now, I have to manually edit claw.data to include a number outside of [0,4].

[mandli]

It would be pretty easy to add. One thing we did do in PyClaw was add another argument for the courant number as some of the more exotic limiters out there required the courant number. You can see the list if you are interested in https://github.com/clawpack/pyclaw/blob/master/src/pyclaw/limiters/tvd.py.