F_C1 return for boundary cell

CeesH · June 18, 2018, 08:52

Hi all,

Quick (and hopefully simple) question - what is the return value of F_C1(f,t) for boundary cells, i.e. where C1 does not exist?

Also, how are cells on interfaces treated in this - there technically is a cell on the other side, but it does not share the same face (and may be non-conformal).

obscureed · June 18, 2018, 10:11

Hi CeesH,

Yes, I can answer the simple question: if(F_C1_THREAD==NULL){ ... } will test whether C1 does not exist.

As far as I'm concerned, interfaces in UDFs are not a simple question, not at all. (Well, most UDFs are fine. But the small subset of UDFs where you want to look up connections -- horrors.) Adaption is also a minefield.

Good luck!
Ed

CeesH · June 18, 2018, 11:15

Thanks! Might be in for some fun then; the eventual UDF has to compute fluxes between cell clusters, which may or may not cross multiple cell zones. But ah well, I guess we don't get paid just to do easy stuff...

Cheers!

obscureed · June 18, 2018, 11:39

Crossing cell zones: not too bad.

Interfaces: you might find that interface cells have no F_C1 -- so, the interface is handled differently. In that case, interfaces might not be too bad, so long as your clusters do not need to cross interfaces. But if it's more complicated than that, or if people are dead-set on clusters crossing interfaces: this is bad enough to go back and question the scope. Multiply the budget by a factor between 10 and infinity. At least propose Phase 1 to get it working with interfaces and adaption specifically ruled out, and then Phase 2 to include them. You might reach retirement before Phase 2 is completed.

Another (maybe obvious) bit of advice: plan from the start how this will work in parallel, unless parallel is ruled out permanently.

Good luck!
Ed

June 18, 2018, 08:52	F_C1 return for boundary cell	#1
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	Hi all, Quick (and hopefully simple) question - what is the return value of F_C1(f,t) for boundary cells, i.e. where C1 does not exist? Also, how are cells on interfaces treated in this - there technically is a cell on the other side, but it does not share the same face (and may be non-conformal).

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June 18, 2018, 10:11		#2
obscureed Senior Member Join Date: Sep 2017 Posts: 246 Rep Power: 11	Hi CeesH, Yes, I can answer the simple question: if(F_C1_THREAD==NULL){ ... } will test whether C1 does not exist. As far as I'm concerned, interfaces in UDFs are not a simple question, not at all. (Well, most UDFs are fine. But the small subset of UDFs where you want to look up connections -- horrors.) Adaption is also a minefield. Good luck! Ed

June 18, 2018, 11:15		#3
CeesH Senior Member Cees Haringa Join Date: May 2013 Location: Delft Posts: 607 Rep Power: 0	Thanks! Might be in for some fun then; the eventual UDF has to compute fluxes between cell clusters, which may or may not cross multiple cell zones. But ah well, I guess we don't get paid just to do easy stuff... Cheers!

June 18, 2018, 11:39		#4
obscureed Senior Member Join Date: Sep 2017 Posts: 246 Rep Power: 11	Crossing cell zones: not too bad. Interfaces: you might find that interface cells have no F_C1 -- so, the interface is handled differently. In that case, interfaces might not be too bad, so long as your clusters do not need to cross interfaces. But if it's more complicated than that, or if people are dead-set on clusters crossing interfaces: this is bad enough to go back and question the scope. Multiply the budget by a factor between 10 and infinity. At least propose Phase 1 to get it working with interfaces and adaption specifically ruled out, and then Phase 2 to include them. You might reach retirement before Phase 2 is completed. Another (maybe obvious) bit of advice: plan from the start how this will work in parallel, unless parallel is ruled out permanently. Good luck! Ed