Thanks Freddie. This clears up a lot. On Thursday, June 13, 2019 at 4:54:04 PM UTC-7, Freddie Witherden wrote: > > Hi Joshua, > > On 13/06/2019 18:29, Joshua Brinkerhoff wrote: > > /Question 1: How does the polynomial order affect the time step required > > for solution stability?/ > > In a very broad sense dt ~ 1/p^2 and so if you increase the polynomial > order you will need to decrease the time-step accordingly. > > > /Question 2: How does the polynomial order relate to the residuals > > produced in the tutorial and their convergence rate?/ > > The polynomial order has no substantial impact on the rate of > convergence per-se. However, it does have an impact on the minimum > residual which can be obtained (for a higher polynomial order enables > you to get closer to the true solution). > > > /Question 3: Why do I see non-monotonic variation in the solution time > > for different polynomial orders?/ > > The Couette flow test case is pathological in the sense it is extremely > small. Run-times are therefore dominated by overhead from Python rather > than actually doing real work. Indeed, you will quite possibly even see > an improvement if you restrict PyFR to a single thread/CPU core. > > For a real-world problem the run-time will increase greatly as the > polynomial order is increased. Of course, in the real-world, as you > increase the polynomial order you typically coarsen your mesh accordingly. > > Regards, Freddie. >
-- You received this message because you are subscribed to the Google Groups "PyFR Mailing List" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send an email to [email protected]. Visit this group at https://groups.google.com/group/pyfrmailinglist. To view this discussion on the web, visit https://groups.google.com/d/msgid/pyfrmailinglist/6737df7c-a27f-4d01-a6ed-ee65ba121e06%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
