View source: R/calc_suit_vect.R
calc_suit_vect | R Documentation |
Calculates a combined value for prey preference and prey suitability standardised to a value between 0 and 1.
calc_suit_vect(nsc, nfish, sc_Linf, prefs, tau)
nsc |
A numeric value representing the number of length classes in the model. |
nfish |
A numeric value representing the number of species in the model. |
sc_Linf |
A numeric vector of length |
prefs |
An array of dimensions |
tau |
A matrix of dimensions |
tau
values are assigned to an array of dimensions nsc
, nfish
, nsc
and nfish
and multiplied by the array prefs
. This creates an array of dimensions nsc
, nfish
, nsc
and nfish
indicating prey suitability. Prey suitability is then standardised to sum to 1 for each predator species in each length class.
A list object of length nfish
. Each element in the list is an array of dimensions nsc
, nsc
and nfish
containing a value between 0 and 1 that represents prey preference and prey suitability for each species and length class.
Hall, S. J., Collie, J. S., Duplisea, D. E., Jennings, S., Bravington, M., & Link, J. (2006). A length-based multispecies model for evaluating community responses to fishing. Canadian Journal of Fisheries and Aquatic Sciences, 63(6):1344-1359.
calc_M2
.
# Set up the inputs to the function - species-independent parameters nfish <- nrow(NS_par) nsc <- 32 maxsize <- max(NS_par$Linf)*1.01 # the biggest size is 1% bigger than the largest Linf l_bound <- seq(0, maxsize, maxsize/nsc); l_bound <- l_bound[-length(l_bound)] u_bound <- seq(maxsize/nsc, maxsize, maxsize/nsc) mid <- l_bound+(u_bound-l_bound)/2 # Set up the inputs to the function - species-specific parameters Linf <- NS_par$Linf # the von-Bertalanffy asymptotic length of each species (cm). W_a <- NS_par$W_a # length-weight conversion parameter. W_b <- NS_par$W_b # length-weight conversion parameter. k <- NS_par$k # the von-Bertalnaffy growth parameter. Lmat <- NS_par$Lmat # the length at which 50\% of individuals are mature (cm). # Get phi_min tmp <- calc_phi(k, Linf, nsc, nfish, u_bound, l_bound, calc_phi_min=FALSE, phi_min=0.1) # fixed phi_min phi_min <- tmp$phi_min # Calculate growth increments tmp <- calc_ration_growthfac(k, Linf, nsc, nfish, l_bound, u_bound, mid, W_a, W_b, phi_min) sc_Linf <- tmp$sc_Linf wgt <- tmp$wgt # Calculate predator-prey size preferences prefs <- calc_prefs(pred_mu=-2.25, pred_sigma=0.5, wgt, sc_Linf) # Calculate prey preference and prey suitability suit_M2 <- calc_suit_vect(nsc, nfish, sc_Linf, prefs, NS_tau)
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