Hi all,
I am utilizing integrate() to get the area below a function that shape
like an exponential, getting very low for higher values of the
horizontal coordinate y.
In the code below, I present the tricky way I can improve the result
obtained. I compare this result with the one I get from Mathematica
and also with the exact solution I have for this particular case.
/*----------
func <- function(y, a, rate){
x <- function(n,rate) {
rate*exp(-n*rate)
}
boi <- function(y,n,a){
w <- y*log(a*n)-lfactorial(y)-a*n
exp(w)
}
f <- function(n){
boi(y,n,a)*x(n,rate)
}
r <- 0
r1 <- 1
x1 <- 0
dx <- 20
while(r1 > 10e-1000){
r1 <- integrate(f,x1,x1+dx)$value
r <- r + r1
x1 <- x1 + dx
}
r + integrate(f,x1,Inf)$valu
}
func(200,0.1,0.1)
----------*/
Altought I get better results, the value of dx must be carefully
selected. So I ask, there is another method that can give me better
results?
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