Richard,
I didn't read the last part of your email that you "do" want to Vectorize your
function. Sorry about that.
Here is a solution using "sapply" to vectorize your function.
f <- function(x, const) 2^x + const
f2 <- function(x, ...) sapply(x, function(x) f(x, ...) )
> integrate(f2, 0.5, 1, const=testval)
1.845111 with absolute error < 2.0e-14
Ravi.
____________________________________________________________________
Ravi Varadhan, Ph.D.
Assistant Professor,
Division of Geriatric Medicine and Gerontology
School of Medicine
Johns Hopkins University
Ph. (410) 502-2619
email: rvarad...@jhmi.edu
----- Original Message -----
From: Richard Morey <r.d.mo...@rug.nl>
Date: Thursday, April 9, 2009 8:10 am
Subject: [R] problems with integrate ... arguments
To: r-help@r-project.org
> Hi everyone,
>
> I saw this problem dealt with here:
>
>
> but no one answered that request that I can tell. I'm having the same
> problem. I'm having problems passing arguments to functions that I'd
> like to integrate. I could swear this worked in the past, but I can't
> get it to work now. I'm running R on Windows.
>
> Here's my toy code to reproduce the problem:
>
>
> R.Version()$version.string
> # [1] "R version 2.8.1 (2008-12-22)"
>
> f=function(x,const)
> 2^x+const
>
> f2=Vectorize(f,c("x"))
>
> testval=2
>
> f2(1:5,testval)
> # [1] 4 6 10 18 34
> # The vectorized function seems to work right.
>
> integrate(f2,.5,1,c=2)
> # Works. Returns
> # 1.845111 with absolute error < 2.0e-14
>
> integrate(f=f2,.5,1,const=testval)
> # Doesn't work. Returns
> # Error in eval(expr, envir, enclos) :
> # ..1 used in an incorrect context, no ... to look in
>
> I understand that I don't have to Vectorize this function for it to
> work, but the more complicated functions I'm using require Vectorization.
>
> Why can't I pass the argument "const" as a variable, instead of a value?
> I don't understand this error.
>
> Thanks in advance,
> Richard Morey
>
> --
> Richard D. Morey
> Assistant Professor
> Psychometrics and Statistics
> Rijksuniversiteit Groningen / University of Groningen
>
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> R-help@r-project.org mailing list
>
> PLEASE do read the posting guide
> and provide commented, minimal, self-contained, reproducible code.
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