These are chat archives for phaustin/numeric_discussion

20th
Sep 2017
Susan Allen
@SusanEAllen
Sep 20 2017 01:09
Lab 3: Q2b and Q3b : state a general trend is good, coming up with an equation is better.
brogalla
@brogalla
Sep 20 2017 17:37
I'm a bit confused about phrasing for Lab 2 Stability problem part 2. It says: "the backward euler and leapfrog are either stable or unstable for the same Δt values." Does for the same Δt refer to the values used in part 1) or to showing whether or not the euler and leapfrog methods are stable or not when they are done with the same timestep values?
Philip Austin
@phaustin
Sep 20 2017 21:33
@brogalla — yes, the idea is to show explicitly that for $\Delta t$ values that are slightly larger or smaller than the critical -2/$\lambda$ that the backward euler and the leapfrog show very different behaviour (i.e. that backward euler is absolutely stable but leapfrog is not)
@tatjanazenker — you can use Figure Error — whatever gets across the difference between the local and global truncation error.
brogalla
@brogalla
Sep 20 2017 23:30
@phaustin thanks!