[R] A function which is a sum of other functions...

Greg Snow 538280 at gmail.com
Fri Dec 20 17:15:01 CET 2013


My first thought was to use Reduce, but I think for this case that is
a bit of overkill.  You can have a vector or list of functions and
just use sapply/lapply on the list of functions then sum the result.
A quick example:

> funs <- c(sin,cos,tan)
> sapply( funs, function(f) f(pi/6) )
[1] 0.5000000 0.8660254 0.5773503
> sum(sapply( funs, function(f) f(pi/6) ))
[1] 1.943376

Just wrap the above in a function with whatever options you want to
use.  If you need the functions to return vectors (of the same length)
then you can still use sapply, but use rowSums, colSums, or apply on
the result instead of sum.

On Thu, Dec 19, 2013 at 12:05 PM, Onur Uncu <onuruncu at gmail.com> wrote:
>
> Dear R Users
>
> I have a list of functions. Each function in the list is a function of single variable. I would like to create a function (of one variable) which represents the sum of all the functions in the list. So, if the functions in my list are f1(x),..,f5(x) then I would like a new function f(x)=f1(x)+f2(x)+...f5(x)
>
> Appreciate any suggestions on how to do this.
>
> I need the above f(x) function because I would like to minimise it with respect to x using the nlm function.
>
> Thanks.
> ______________________________________________
> 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.



-- 
Gregory (Greg) L. Snow Ph.D.
538280 at gmail.com



More information about the R-help mailing list