scaleModel: Change scale of the model

In mizer: Dynamic Multi-Species Size Spectrum Modelling

Change scale of the model

Description

The abundances in mizer and some rates depend on the size of the area to which they refer. So they could be given per square meter or per square kilometer or for an entire study area or any other choice of yours. This function allows you to change the scale of the model by automatically changing the abundances and rates accordingly.

Usage

scaleModel(params, factor)

Arguments

params	A MizerParams object
factor	The factor by which the scale is multiplied

Details

If you rescale the model by a factor c then this function makes the following rescalings in the params object:

• The initial abundances are rescaled by c.

• The search volume is rescaled by 1/c.

• The resource carrying capacity is rescaled by c

• The maximum reproduction rate R_{max} is rescaled by c.

The effect of this is that the dynamics of the rescaled model are identical to those of the unscaled model, in the sense that it does not matter whether one first calls scaleModel() and then runs a simulation with project() or whether one first runs a simulation and then rescales the resulting abundances.

Note that if you use non-standard resource dynamics or other components then you may need to rescale additional parameters that appear in those dynamics.

In practice you will need to use some observations to set the scale for your model. If you have biomass observations you can use calibrateBiomass(), if you have yearly yields you can use calibrateYield().

Value

The rescaled MizerParams object

mizer documentation built on Oct. 17, 2024, 9:07 a.m.