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File contents
# aspm.r
# aspm: Performs forward simulation of populations, given values of parameters
aspm<-function(Fvec,Rvec){
Yhat<-NULL
Bhat<-NULL
Rtemp<-Rvec[1]
#N0<-Ninit # First start-of-year stock size - fixed
N0<-Rtemp*exp(-cumsum(c(0,M[1:(length(M)-1)]))) # First start-of-year stock size - equil.
for(year in 1:totyrs){
baseF<-Fvec[year] # Base fishing mortality
F0<-baseF*selpat # Fishing mortality during the year
Ntemp<-N0*exp(-F0-M) # Forw proj - gives ages 2:(g+1)
Noldest<-Ntemp[g]+Ntemp[g+1] # Allow for plus-group
C<-(F0/(F0+M))*(1-exp(-(F0+M)))*N0
Ytemp<-sum(C*w) # Total landings
#print(Ytemp)
Yhat<-c(Yhat,Ytemp)
Bhat<-c(Bhat,sum(N0*w))
Rtemp<-Rvec[year]
N1<-c(Rtemp,Ntemp[1:(g-1)],Noldest)# Set up stock at end of year
N0<-N1 # Prepare for next round
}
return(list(Yhat=Yhat,Bhat=Bhat))
}