From: Paul Smith <phhs80_at_gmail.com>

Date: Thu, 21 Feb 2008 14:07:44 +0000

R-help_at_r-project.org mailing list

https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Thu 21 Feb 2008 - 14:12:07 GMT

Date: Thu, 21 Feb 2008 14:07:44 +0000

On Tue, Feb 19, 2008 at 11:07 PM, Chris Rhoads
<c-rhoads_at_northwestern.edu> wrote:

> To start, let me confess to not being an experienced programmer, although I have used R fairly

*> extensively in my work as a
**> graduate student in statistics.
**>
**> I wish to find the root of a function of two variables that is defined by an integral which must be
**> evaluated numerically.
**>
**> So the problem I want to solve is of the form: Find k such that f(k)=0, where f(y) = int_a^b
**> g(x,y) dx. Again, the integral
**> involved must be done numerically.
**>
**> I'm told by a friend who knows programming, but not R, that what I need to do is create something
**> like a "local environment"
**> within which I could create a placeholder for x. So I want to make something like the following work.
**>
**> f(var) <- function(var) {
**>
**> cons <- var
**>
**> g <- function(x,cons) {h(x,cons)}
**>
**> ret <- function(cons) integrate(g(x,cons),a,b)$value
**> ret
**> }
**>
**> I could then use (e.g.) a Newton Raphson algorithm to find the root of the function"f".
*

Can you Chris provide us an example with concrete functions? To us, it would be easier to think about a concrete example.

Paul

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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Thu 21 Feb 2008 - 14:12:07 GMT

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