[R] Retrieving value computed in inner function call
Dear R users,
Consider the following example function:
f = function(a,b) {
g = function(x) a*x + b
h = function(x) g(x)^2 + x^2
opt = optimize(h,lower = -1, upper = 1)
x.min = opt$minimum
h.xmin = opt$objective
g.xmin = g(x.min)
return(c(x.min, h.xmin, g.xmin))
}
In my real problem the function that plays the role of "g" is costly
to compute. Now, to minimize "h", "optimize" calls "h" with different
values of x. In particular, at the end of the optimization, "h" would
be called with argument x.min, the minimizer of h(x). Therefore,
buried somewhere, there has to be a call to "g" with argument x=x.min
which I would like to retrieve in order to avoid the extra call to
"g" in the line before the return. Can this be done without too much pain?
I'd very much appreciate any help.
Juan Pablo Lewinger
Department of Preventive Medicine
University of Southern California
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Re: [R] Retrieving value computed in inner function call
Check out:
http://finzi.psych.upenn.edu/R/Rhelp02a/archive/83547.html
On 9/12/06, Juan Pablo Lewinger <[EMAIL PROTECTED]> wrote:
> Dear R users,
>
> Consider the following example function:
>
> f = function(a,b) {
>g = function(x) a*x + b
>h = function(x) g(x)^2 + x^2
>opt = optimize(h,lower = -1, upper = 1)
>x.min = opt$minimum
>h.xmin = opt$objective
>g.xmin = g(x.min)
>return(c(x.min, h.xmin, g.xmin))
> }
>
> In my real problem the function that plays the role of "g" is costly
> to compute. Now, to minimize "h", "optimize" calls "h" with different
> values of x. In particular, at the end of the optimization, "h" would
> be called with argument x.min, the minimizer of h(x). Therefore,
> buried somewhere, there has to be a call to "g" with argument x=x.min
> which I would like to retrieve in order to avoid the extra call to
> "g" in the line before the return. Can this be done without too much pain?
>
> I'd very much appreciate any help.
>
>
>
> Juan Pablo Lewinger
> Department of Preventive Medicine
> University of Southern California
>
> __
> R-help@stat.math.ethz.ch 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.
>
__
R-help@stat.math.ethz.ch 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.
Re: [R] Retrieving value computed in inner function call
Though not obvious at first the posting you pointed me too is very helpful
indeed. Thanks a lot Gabor.
Juan Pablo
At 08:48 PM 9/12/2006 -0400, Gabor Grothendieck wrote:
>Check out:
>
>http://finzi.psych.upenn.edu/R/Rhelp02a/archive/83547.html
>
>On 9/12/06, Juan Pablo Lewinger <[EMAIL PROTECTED]> wrote:
>>Dear R users,
>>
>>Consider the following example function:
>>
>>f = function(a,b) {
>>g = function(x) a*x + b
>>h = function(x) g(x)^2 + x^2
>>opt = optimize(h,lower = -1, upper = 1)
>>x.min = opt$minimum
>>h.xmin = opt$objective
>>g.xmin = g(x.min)
>>return(c(x.min, h.xmin, g.xmin))
>>}
>>
>>In my real problem the function that plays the role of "g" is costly
>>to compute. Now, to minimize "h", "optimize" calls "h" with different
>>values of x. In particular, at the end of the optimization, "h" would
>>be called with argument x.min, the minimizer of h(x). Therefore,
>>buried somewhere, there has to be a call to "g" with argument x=x.min
>>which I would like to retrieve in order to avoid the extra call to
>>"g" in the line before the return. Can this be done without too much pain?
>>
>>I'd very much appreciate any help.
>>
>>
>>
>>Juan Pablo Lewinger
>>Department of Preventive Medicine
>>University of Southern California
>>
>>__
>>R-help@stat.math.ethz.ch 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.
__
R-help@stat.math.ethz.ch 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.
