log for complex

[H. S. Teoh]

On Wed, Mar 07, 2018 at 10:47:40AM +0000, J-S Caux via Digitalmars-d-learn wrote:
> On Wednesday, 7 March 2018 at 10:28:23 UTC, Simen Kjærås wrote:
> > On Wednesday, 7 March 2018 at 10:10:49 UTC, J-S Caux wrote:
> > > On Wednesday, 7 March 2018 at 08:04:36 UTC, Simen Kjærås wrote:
> > > > auto log(T)(Complex!T x) {
> > > >     import std.math : log;
> > > >     return Complex!T(log(abs(x)), arg(x));
> > > > }
> > > 
> > > Yes indeed I can do this, but isn't this inefficient as compared
> > > to what it should be? The internals of arg are presumable already
> > > doing part of/all the necessary work.
> > 
> > arg is just atan2 in disguise, and doesn't do any logarithms. I
> > mean, in a way it does, but it's really just a fpatan instruction. I
> > don't expect there to be many optimization opportunities here.
[...]
> OK thanks Simen. Should your suggestion for repairing this omission be
> filed as a bugreport? I can of course implement it locally for myself,
> but the language should really provide this function directly.

Yes, please file a bug.


T

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