Re: [boost] [proto] transforms && rvalue refs

Subject: Re: [boost] [proto] transforms && rvalue refs
From: Joel Falcou (joel.falcou_at_[hidden])
Date: 2009-03-30 13:27:57

troy d. straszheim a écrit :
>
> When it is time to evaluate the expression, the grammar fires the 
> transform for exp(B) first.  It creates a temporary T with the same 
> dimensions as B and and a function is called to compute the result 
> into T.  Now 'T * C' happens.  In this case there is an available 
> temporary, 'T', so the result can go right in to T.  T is returned and 
> moved in to A.  Done...  at least, that's the idea.
>
No, when you evaluate the expression, you iterate via a for loop nest 
over the elements of all array, recursively calling the elementwise 
version of exp and *. The context just evaluate one element at a time. 
In the end, the only temporary created are those from the elementwise 
function return.

Expression Tempalte never create copy of their terminal object unless 
requested

-- 
___________________________________________
Joel Falcou - Assistant Professor
PARALL Team - LRI - Universite Paris Sud XI
Tel : [phone]