second_order_w: Get or set the second_order_w flags

Description

Controls whether mizer uses numerical methods that are precise to second order in \(\Delta w\).

Usage

second_order_w(params)
second_order_w(params) <- value

Value

second_order_w(): A named list with entries flux (character) and bin_average (logical).

second_order_w<-: A MizerParams object with the second_order_w

flags updated and, when bin_average is changed, all model parameters recalculated via setParams().

Arguments

params: A MizerParams object.
value: A single logical value (TRUE or FALSE) which sets both entries, a single flux scheme name ("upwind", "van_leer" or "centred") which sets only flux, or a named vector with entries flux (logical or scheme name) and/or bin_average (logical).

Details

The slot is a named list with entries:

flux: The advective-flux reconstruction scheme used in the numerical solver. "upwind" is the first-order upwind scheme. "van_leer" is the second-order scheme with the total-variation- diminishing van Leer limiter, which keeps abundances non-negative. "centred" is the second-order scheme with the unlimited centred flux, which is genuinely second order even at extrema but is not monotonicity-preserving (it can produce small over/undershoots and is best used with some physical diffusion).
bin_average: Logical. Controls whether bin-averaging is used for quantities that need it in order to be second-order precise in bin size. When FALSE, point-sampling at the left bin edge is used.

When flux is "upwind" and bin_average is FALSE (the defaults), mizer preserves the behaviour of previous mizer versions. Setting both to their second-order values gives a consistently second-order model.

The setter accepts a single logical value (which sets both entries), a single scheme name (which sets only flux), or a named vector to set individual entries. The setter re-runs setParams() to rebuild precomputed arrays when bin_average is changed.