The four-parameter growth function from Schnute (1981).
The four-parameter growth function from Schnute (1981).
Schnute( t, case = 1, t1 = NULL, t3 = NULL, L1 = NULL, L3 = NULL, a = NULL, b = NULL )
t |
A numeric vector of ages over which to model growth. |
case |
A string that indicates the case of the Schnute growth function to use. |
t1 |
The (young) age that corresponds to |
t3 |
The (old) age that corresponds to |
L1 |
The mean size/length at |
L3 |
The mean size/length at |
a |
A dimensionless parameter that is related to the time/age at the inflection point. |
b |
A dimensionless parameter that is related to size/length at the inflection point. |
Schnute returns a predicted size given the case of the function and the provided parameter values.
None specifically, but 12-Individual Growth is related.
Derek H. Ogle, derek@derekogle.com
Schnute, J. 1981. A versatile growth model with statistical stable parameters. Canadian Journal of Fisheries and Aquatic Sciences 38:1128-1140.
See vbFuns, GompertzFuns, RichardsFuns, logisticFuns, and SchnuteRichards for similar functionality for other models.
## See the formulae
growthFunShow("Schnute",1,plot=TRUE)
growthFunShow("Schnute",2,plot=TRUE)
growthFunShow("Schnute",3,plot=TRUE)
growthFunShow("Schnute",4,plot=TRUE)
## Simple examples
ages <- 1:15
s1 <- Schnute(ages,case=1,t1=1,t3=15,L1=30,L3=400,a=0.3,b=1)
s2 <- Schnute(ages,case=2,t1=1,t3=15,L1=30,L3=400,a=0.3,b=1)
s3 <- Schnute(ages,case=3,t1=1,t3=15,L1=30,L3=400,a=0.3,b=1)
s4 <- Schnute(ages,case=4,t1=1,t3=15,L1=30,L3=400,a=0.3,b=1)
plot(s1~ages,type="l",lwd=2)
lines(s2~ages,lwd=2,col="red")
lines(s3~ages,lwd=2,col="blue")
lines(s4~ages,lwd=2,col="green")Please choose more modern alternatives, such as Google Chrome or Mozilla Firefox.