[R] Plotting several functions in the same display (again)
Julio Sergio
juliosergio at gmail.com
Thu Apr 4 17:38:03 CEST 2013
To superimpose two functions plots in the same page. The functions L0
and L1, as defined below, I use the following code:
# An accumulative normal distribution function with
# several parametres
f0 <- function(mu, xm, ds, n) {
1 - pnorm((xm-mu)/(ds/sqrt(n)))
}
f1 <- function(mu,n) f0(mu, 386.8, 48, n)
# Two functions with just the parameter mu
L0 <- function(mu) f1(mu, 36)
L1 <- function(mu) f1(mu,100)
plot(L0,ylim=c(0,1),xlim=c(360,420))
curve(L1,add=T)
However, I'm puzzled with a problem in the same line: When I passed a
"function producer" to plot, again it worked well; however it didn't work in
the same way when trying to use this same argument in curve. See what I'm
talking about:
# A particular normal distribution function:
dn8 <- function(z,m) dnorm(z,m,8) # norm dist with sd=8
# A function that produces functions:
# returns a function such that given a mean(i) depends only
# on z
fi <- function(i) function(z) dn8(z,i)
plot(fi(370),xlim=c(360,420)) # Works well!
curve(fi(380),add=T) # This doesn't work
# However, if I put it in this way, surprisingly, it works!
ff <- fi(380)
curve(ff,add=T)
I cannot understand this behaviour. Could anyone give me some feedback on
this?
Thanks,
-Sergio.
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