[Liboil] complex types?

[Stephane Fillod]

On Mon, Nov 14, 2005 at 06:54:51PM -0800, David Schleef wrote:
[..]
> > I mean 'float *' as in 'float *d_2xn' that has n interleaved real and
> > imag float values. Speed can be one reason, existing data model of 
> > applications and/or hardware devices is another one.
> 
> Ok, good.
> 
> > oil_sincos_f64()-like prototype does not fit my need, because "complex" 
> > args are not interleaved.
> 
> How about:
> 
> oil_sincos_interleaved_f64(double *d_2xn, double *s1_1, double *s2_1,
> int n)
> {
>   int i;
>   for(i=0;i<n;i++){
>     d_2xn[i*2 + 0] = cos(*s1_1 + *s2_1 * i);
>     d_2xn[i*2 + 1] = sin(*s1_1 + *s2_1 * i);
>   }
> }

With stride or without ? Should stride be present everywhere?
Personaly, I don't need stride in forseeable future.

> Also,
> 
> oil_complexmult_f64 (double *d_2xn, double *s1_2xn, double *s2_2xn, int
> n)
> {
>   int i;
>   double a, b, c, d;
>   for(i=0;i<n;i++){
>     a = s1_2xn[2*i + 0];
>     b = s1_2xn[2*i + 1];
>     c = s2_2xn[2*i + 0];
>     d = s2_2xn[2*i + 1];
>     d_2xn[2*i + 0] = a * c - b * d;
>     d_2xn[2*i + 1] = a * d + b * c;
>   }
> }
> 
> So in other words, complex would be a convention, not a new type,
> somewhat like ARGB.  BTW, I'm trying to avoid the issue in order to
> take a wait-and-see approach.

Good, I like it.

Can you please take care of adding the 2xn support and OIL_DEFINE_CLASS
handling ? I'm not confortable enough yet with the test harness.

> > BTW, I don't understand why offset and interval
> > are passed by address and not by value in oil_sincos_f64.
> 
> Everything is pass-by-address because it's about a million times
> easier on the automatic testing and marshalling code.  And that's
> one of the reasons why liboil exists instead of being prototype
> code in my random hacking directory.

Too bad for the pass-by-address on simple args :-(

On a different topic, can you please explain what is the convention 
about implementation modifiers like "_i10", "_l10" ? I will need
them for sincos.

-- 
Stephane