Complex numbers in compilers - upcoming GNU Tools Cauldron.

[Martin Uecker]

Am Dienstag, dem 12.09.2023 um 11:25 +0200 schrieb Richard Biener via Gcc:
> On Tue, Sep 5, 2023 at 10:44 PM Toon Moene <toon@moene.org> wrote:
> > 
> > This is going to be an interesting discussion.
> > 
> > In the upcoming GNU Tools Cauldron meeting the representation of complex
> > numbers in GCC will be discussed from the following "starting point":
> > 
> > "Complex numbers are used to describe many physical phenomenons and are
> > of prime importance in data signal processing. Nevertheless, despite
> > being part of the C and C++ standards since C99, they are still not
> > completely first class citizens in mainstream compilers."
> > 
> > *This* is from the Fortran 66 Standard (http://moene.org/~toon/f66.pdf -
> > a photocopy of the 1966 Standard):
> > 
> > - - - - -
> > 
> > Chapter 4. Data Types:
> > ...
> > 4.2.4 Complex Type.
> > 
> > A complex datum is processor approximation to the value of a complex number.
> > ...
> > 
> > - - - - -
> > 
> > I can recall people complaining about the way complex arithmetic was
> > handled by compilers since the late 70s.
> > 
> > This is even obvious in weather forecasting software I have to deal with
> > *today* (all written in Fortran). Some models use complex variables to
> > encode the "spectral" (wave-decomposed) computations in parts where that
> > is useful - others just "degrade" those algorithms to explicitly use reals.
> 
> Lack of applications / benchmarks using complex numbers is also a
> problem for any work on this.
> 

I could probably provide some examples such as a FFT, 
complex Gaussian random number generation, mandelbrot
set computation, etc.

Martin