[R] when vectorising does not work: silent function fail?

[Juliet Hannah]

>
> Also, you probably get less data copying by using a for() or while() loop
> than by using apply() in this context.


Why may there be less data copying with "for" and "while" compared to apply?


>
> Finally, the overhead of formula parsing and model matrix construction
> repeated thousands of times probably dominates this computation; if it isn't
> just a one-off it would probably be worth a lower-level implementation.
>

Does "lower-level implementation" mean code this outside of R.

Thanks!

Juliet