R/dget_LUHj.R

In Echinophoria/DEB_output: Dynamic Energy Budget exploration tools

#'@export
dget_LUHj <- function (a, LUH, p, pars){
  # this function is used to model the changes in L, E and maturity between
  # birth and the start of metamorphosis. It gives daily changes
  # p = a list containing  DEB parameters
  
  # pars: a 2-vector with
  # lb = scaled length at birth (cm)
  # f = scaled functional response (only for assimilation)
  
  # LEH: a 3-vector with initial conditions
  # L = current structural length (cm)
  # E = current scaled energy reserves (d cm^2)
  # H = current scaled maturity level (d cm^2)
  
  # return a vector (dL, dU, dH) where
  # dL = cm, growth of structure
  # dU = d cm^2, change in reserves
  # dH = d cm^2, change in maturity level
  
  L = LUH[1]  # cm, structural length
  U = LUH[2]  # d cm^2, scaled reserves
  H = LUH[3]  # d cm^2, scaled maturity
  
  lb=pars[1]  # -, scaled birth size
  f =pars[2]  # -, scaled functional response during growth
  
  g = p$g      # -, investment ratio
  kap = p$kap  # -, fraction invest in somatic growth and maintenance
  k = p$k      # -, maintenance ratio
  lT =p$l_T    # -, scaled heating surface
  Lm = p$L_m   # cm, maximum length
  kM = p$k_M   #-/d, somatic maintenance rate coefficient
  k= p$k       # cm/d, conductivity
  
  l= L/Lm
  uE = U*g^2*kM^3/v^2
  uH = H*g^2*kM^3/v^2
  
  rj = (g * uE/ lb - l^3 * lT/ lb - l^3)/ (uE + l^3) # scaled exponential growth rate between b and j
  dl = l * rj*kM/ 3
  duE = (f * l^3/ lb - uE * (g/ lb - rj))*kM
  duH = ((1 - kap) * uE * (g/ lb - rj) - k * uH)*kM
  dL = dl * Lm
  dU = duE * v^2/ g^2/ kM^3
  dH = duH * v^2/ g^2/ kM^3
  
  
  return(list(c(dL, dU, dH)))
}