dFJ_dt_1state: Temporal dynamics of F or J

In cboettig/bs-tipping: Bifurcation or State Tipping in a Trophic Cascade Experiment

Description

Temporal dynamics of F or J, but as a function of F or J and parameters (not other state variables)

Usage

dFJ_dt_1state(State0, pars, stateName = c("J0", "F0"), parts = FALSE)

Arguments

State0	abundance of planktivorous fish (F0) or abundance of juvenile bass (J0)
pars	named vector of parameters found in ecoStep. At a minimum, qE needs to be supplied. Optionally, other parameter arguments can be supplied here, but if they aren't, they are taken from the formals (defaults) of ecoStep.
stateName	a length-1 character indicating whether the value supplied (and value returned) pertains to "F0" (planktivores) or "J0" (juvenile bass). Juveniles ("J0") is chosen by default.
parts	Logical, if FALSE (default), function returns the rate of change in the indicated state variable. If TRUE, function returns the rate of 'growth' (>=0) and the rate of 'consumption' (<=0) for the indicated state variable.

Value

numeric value indicating temporal rate of change of F or J; or, if parts==TRUE, a named vector of length 2 indicate the growth and consumption components of the temporal rate of change of F or J.

Examples

getRoot(c(A0=1, F0=1, J0=1), pars=c(qE=0.5)) # find equilibria when bass are rare
dFJ_dt_1state(State0=17.890184, pars=c(qE=0.5), stateName="F0") # F0 set to equilibrium when bass start as rare
dFJ_dt_1state(State0=3.06, pars=c(qE=0.5), stateName="J0") # J0 set to equilibrium when bass start as rare

getRoot(c(A0=1000, F0=1, J0=1000), pars=c(qE=0.5)) # find equilibria when bass are abundant
dFJ_dt_1state(State0=0.06712064, pars=c(qE=0.5), stateName="F0") # F0 set to equilibrium when bass start as abundant
dFJ_dt_1state(State0=992.5699, pars=c(qE=0.5), stateName="J0") # J0 set to equilibrium when bass start as abundant

getRoot(c(A0=1, F0=1, J0=1), pars=c(qE=0.65)) # find equilibria when bass are rare
dFJ_dt_1state(State0=100, pars=c(qE=0.65), stateName="F0") # F0 set to equilibrium when bass start as rare # WTF?!
fishStep(X=c(A0=6.275129e-18, F0=100, J0=1.443280e-17))
dFJ_dt_1state(State0=1.44e-17, pars=c(qE=0.65), stateName="J0") # J0 set to equilibrium when bass start as rare # Makes sense

getRoot(c(A0=1000, F0=1, J0=1000), pars=c(qE=0.65)) # find equilibria when bass are abundant
dFJ_dt_1state(State0=0.09136212, pars=c(qE=0.65), stateName="F0") # check planktivore equation for rate of change
dFJ_dt_1state(State0=838.3849, pars=c(qE=0.65), stateName="J0") # check juvenile equation for rate of change
fishStep(X=c(A0=364.51517642, F0=0.09136212, J0=838.38490576)) # re-examine rates of change of fish near equilibrium

cboettig/bs-tipping documentation built on May 5, 2019, 7:08 a.m.