Subject: Re: [boost] Interest in updated expression template library?
From: Zach Laine (whatwasthataddress_at_[hidden])
Date: 2017-01-10 15:07:52
On Tue, Jan 10, 2017 at 1:45 PM, Mathias Gaunard <
mathias.gaunard_at_[hidden]> wrote:
> On 10 January 2017 at 14:35, Zach Laine <whatwasthataddress_at_[hidden]>
> wrote:
>
> I've personally played a lot with expression templates, with and without
> Proto.
> Very quickly it becomes hairy, consumes huge amounts of memory that is
> never reclaimed, and takes very long to compile.
> I don't know how much better it is with Yap, but that's definitely a major
> problem and any new solution should try to address it.
> Symbols need to be short, and no evaluation should ever depend on the
> scalability of overloading or partial template specializations.
>
I agree with all of these complaints. This is in fact why I wrote Yap.
The compile times are very good, even for an obnoxious number of terminals
(thousands), and there is no memory allocated at all -- or did you mean
compiler memory usage? I haven't looked at that.
> The design used by Eigen or by some valarray implementations, while not
> necessarily the most elegant, is simple and scales well, but involves
> coupling the representation of the tree with its evaluation.
My hope is that the Yap design is easy enough to use that custom ET code is
no longer necessary.
Zach