[R] integrate a function in R

[Dimitris Rizopoulos]

Hi Liu,

you should take advantage of lexical scoping, i.e.,


zfz <- function(z) z*dnorm(x=z, mean=u)
us <- seq(-1, 1, length=10)
out <- numeric(length(us))
for(i in seq(along=us)){
    u <- us[i]
    out[i] <- integrate(zfz, 0, u+3)$value
}
out


I hope it helps.

Best,
Dimitris

----
Dimitris Rizopoulos
Ph.D. Student
Biostatistical Centre
School of Public Health
Catholic University of Leuven

Address: Kapucijnenvoer 35, Leuven, Belgium
Tel: +32/16/396887
Fax: +32/16/337015
Web: http://www.med.kuleuven.ac.be/biostat/
     http://www.student.kuleuven.ac.be/~m0390867/dimitris.htm


----- Original Message ----- 
From: "yyan liu" <zhliur at yahoo.com>
To: <r-help at stat.math.ethz.ch>
Sent: Thursday, October 28, 2004 12:56 AM
Subject: [R] integrate a function in R


> Hi:
>  I want to integrate the following function with
> respect to "z", "u" is another argument in the
> function. My program is a loop and in each loop the
> argument "u" will be given a specified numeric values.
> But how can I use the "integrate" function with "u" in
> R?
>  The function is:
> zfz<-function(z,u)
> {
>  return(z*dnorm(z,u,1) )
> }
>
> And in each loop, the integration interval is [0,u+3].
> I can not just use integrate(zfz,0,u+3) because "u"
> can not be specified.
> Thank you!
>
> liu
>
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