Challenge: Automatic differentiation in D

[Steve Teale]

Bill Baxter Wrote:

> > Bill,
> >
> > D4 maybe. In the present mood I think you are spitting in the wind!
> 
> I'm just proposing it as a fun project if anyone is interested.
> Shouldn't require any compiler changes.  Unless roadblocks are found
> that require some compiler changes, in which case it's better to know
> about those now than later on.   I see AD as a category of interesting
> numerical techniques that a sufficiently advanced compiler can make
> much less painful to use.  Like expression templates.  I think D2 has
> most of what would be needed already.  The basic idea of AD (forward
> AD, anyway) is pretty simple and quite elegant IMO, and worth learning
> about anyway, for anyone interested in numerical computing,
> computational physics, etc.
> 
> --bb

Bill,

Has there been a discussion about expression templates - I have never been able to understand why they only apply to declarations. That sounds interesting.

Steve