| Fnorm {VGAM} | R Documentation |
Density, distribution function, quantile function and random generation for the (generalized) folded-normal distribution.
dfnorm(x, mean=0, sd=1, a1=1, a2=1) pfnorm(q, mean=0, sd=1, a1=1, a2=1) qfnorm(p, mean=0, sd=1, a1=1, a2=1, ...) rfnorm(n, mean=0, sd=1, a1=1, a2=1)
x, q |
vector of quantiles. |
p |
vector of probabilities. |
n |
number of observations. Must be a positive integer of length 1. |
mean, sd |
see rnorm. |
a1, a2 |
see fnormal1. |
... |
Arguments that can be passed into uniroot.
|
See fnormal1, the VGAM family function
for estimating the parameters,
for the formula of the probability density function and other details.
dfnorm gives the density,
pfnorm gives the distribution function,
qfnorm gives the quantile function, and
rfnorm generates random deviates.
qfnorm runs very slowly because it calls
uniroot for each value of the argument p.
The solution is consequently not exact; the ... can be used
to obtain a more accurate solution if necessary.
T. W. Yee
## Not run:
m = 1.5; SD=exp(0)
x = seq(-1, 4, len=501)
plot(x, dfnorm(x, m=m, sd=SD), type="l", ylim=0:1, las=1,
ylab=paste("fnorm(m=", m, ", sd=", round(SD, dig=3), ")"), col="blue",
main="Blue is density, red is cumulative distribution function",
sub="Purple lines are the 10,20,...,90 percentiles")
lines(x, pfnorm(x, m=m, sd=SD), col="red")
abline(h=0)
probs = seq(0.1, 0.9, by=0.1)
Q = qfnorm(probs, m=m, sd=SD)
lines(Q, dfnorm(Q, m=m, sd=SD), col="purple", lty=3, type="h")
lines(Q, pfnorm(Q, m=m, sd=SD), col="purple", lty=3, type="h")
abline(h=probs, col="purple", lty=3)
max(abs(pfnorm(Q, m=m, sd=SD) - probs)) # Should be 0
## End(Not run)