Don Clugston wrote:
On 28 March 2010 17:35, Lars Tandle Kyllingstad <[email protected]> wrote:
I've committed an update of my std.complex proposal:
http://github.com/kyllingstad/ltk/blob/master/ltk/complex.d
The current status is as follows:
- Changed mod() to abs(), like Don requested. I'll implement abs() with
std.math.hypot() as soon as bug 4023 is fixed.
Yup, that's an embarrassing one. I'll get it fixed ASAP.
Thanks!
[...]
Two questions:
I had a look at the implementation of std.numeric.FPTemporary, and noted
that it's just an alias for real, regardless of the specified type. (Also,
the std.math.hypot() function is just defined for the real type.) Can we be
sure this is always what the user wants? Won't using double be faster in
some cases, or is it so that calculations are done with 80-bit precision
anyway?
On x86, real is always better. On other architectures, the definition
of FPTemporary will be different.
As you may have seen, I've put in two different multiplication formulae. I
did this because I read that multiplication is slow on some architectures,
and the first formula has fewer multiplications. On my machine, however,
the second (and "standard") one is slightly faster. Do you know which
architecures this refers to, and are any of them relevant for D?
I don't think that would be true of any architectures made in the last
twenty years.
Worrying about that would be premature optimisation.
All right, I'll remove it then. Thanks again!
-Lars
WRT both these last two points, array operations on complex types is
the place where optimisation really matters.
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