[Rcpp-devel] Speed up of the data.frame creation in DataFrame.h

[Christian Gunning]

> Subject: Re: [Rcpp-devel] Speed up of the data.frame creation in
>         DataFrame.h
> Message-ID: <757EF798-6BC6-4150-93CD-B5F23D9014C7 at gmail.com>
> Content-Type: text/plain; charset=windows-1252
>
> The fix I was proposing actually has implications much deeper than I thought. I would need to investigate further and will take no action at this time.

Hello list, long time no see!

Dmitry,
Have you identified any other consequences than what Romain pointed
out?  This information would be useful for the rest of us.

Some key points that I agree with:
 * as per Dirk: this is a nice little piece of sleuthing.  Your
benchmarking shows that the effect is significant.
 * as per your comments: a key intent of Rcpp is allow the user the
freedom to acheive optimization and do their own error checking.
  * as per Romain: let's not break things.

It seems possible address all of these points, perhaps with a
dedicated function, as per your comments.  I can help with this, if
you're interested.

Key question: what is the intended behavior of this function?  E.g.,
throw an exception on length mismatch?  My vote is for a limited
function that deals with a limited number of use cases and provides
reasonable error-checking (e.g. throws exception for input outside
scope), versus a logic-heavy function that handles recycling, for
example.  Does this match your use-case?

-Christian

-- 
A man, a plan, a cat, a ham, a yak, a yam, a hat, a canal – Panama!