[R-pkg-devel] Effieciency drop in do.call?

[peter dalgaard]

If it was just about args evaluation, then the slowness would be in the list() call, no?
An accidental deparse of a large structure could well be the culprit.

-pd


> On 19 Nov 2018, at 18:53 , Gabor Grothendieck <ggrothendieck using gmail.com> wrote:
> 
> The do.call version evaluates all arguments while the normal version
> may not depending on the function.  There could also be a difference
> if the function uses non-standard evaluation since in that case the
> two could be passing different different argument values.
> 
> For an example of the second case,
> 
>  f <- function(x) deparse(substitute(x))
> 
>  f(pi)
>  ## [1] "pi"
> 
>  do.call("f", list(pi))
>  ## [1] "3.14159265358979"
> 
> On Mon, Nov 19, 2018 at 11:50 AM Paul Buerkner <paul.buerkner using gmail.com> wrote:
>> 
>> Hi all,
>> 
>> today, I stumbled upon a puzzling (to me) problem apparently related to
>> do.call() that resulted
>> in an efficiency drop of multiple orders of magnitudes compared to just
>> calling the function directly (multiple minutes as compared to one second).
>> 
>> That is
>> 
>> fun(a = a, b = b, c = c, ...)
>> 
>> took one second, while
>> 
>> args <- list(a = a, b = b, c = c, ...)
>> do.call(fun, args)
>> 
>> took multiple minutes.
>> 
>> In my package (brms), I use do.call in various places but only in one it
>> resulted in this
>> efficiency drop.
>> 
>> Before I try to make a reproducible example, I wanted to ask if there are
>> any known issues
>> with do.call that may explain this?
>> 
>> Paul
>> 
>>        [[alternative HTML version deleted]]
>> 
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> 
> 
> 
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Peter Dalgaard, Professor,
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