[RFC PATCH] gas model: use virial cubic polynomial form

[Dirk Hohndel]

On Thu, Mar 03, 2016 at 09:46:19PM -0800, Linus Torvalds wrote:
> 
> So for this to make sense, we'd need to feel that performance matters. We 
> *do* end up doing the gas use for each plot point, so it's not like this 
> function might not get called a lot.
> 
> But compiler options will change the code generation even more than this 
> ever will, and aggressive compiler optimizations would have made the old 
> code better too (ie just inlining and CSE on the pressure power series 
> would do good things to the thing without this patch too).
> 
> In other words: I think this patch is correct, and it *does* make the code 
> faster. But do we even care at this point?

Obviously, fewer computations are good. I semi-concur with Robert that we
are over engineering this, but I think the rationale of using the virial
form makes sense. So I'm inclined to take this patch as it both uses a
more reasonable formula AND reduces computational complexity.

/D