Re: [boost] RFC: runtime-flexible arrays

Subject: Re: [boost] RFC: runtime-flexible arrays
From: Joel Falcou (joel.falcou_at_[hidden])
Date: 2012-02-16 14:10:10

Sorry for the noise ::

the loop nest generator is basically a recursive function that gets 
dimensions informations from a fusion sequence of dimension set.
The storage order is applied as a permutation on this sequence and 
passed to the generator. the shuffled position is passed to the whole 
expression tree and when we're down in a terminal, it get applied again 
to grant access to the proper memory size.
The shuffling of position is done at compile time usign MPL on 
fusion::at_c parameter and incurs no overhead.

That's the basic theory. Now above 2D, most array representation and 
memory access incurs a high payload on registers and may limit 
performances. So we treat nD array as a flattened 2D one and aggregate 
outer dimensions after shuffling.