On Saturday, 30 May 2015 at 12:34:21 UTC, Rikki Cattermole wrote:
On 30/05/2015 11:46 p.m., short2cave wrote:
Consider this struct:
---
Foo
{
uint a,b,c;
float d,e,f;
}
---
in a collection:
---
Foo[] foos;
---
Looping a particular member is not cache friendly
---
foreach(foo;foos){/*foo.a = ...*/}
---
but to write clear, understable, structured code, the struct
is necessary.
So, is it possible to imagine an abstraction such as
---
FooData
{
uint[] a,b,c;
float[] d,e,f;
Foo[] items(){}
}
---
that would allow to loop over the data in a cache-friendly way
?
You think that an item as the member but they are actually
stored using
another memory layout ?
A template for this would be particularly usefull:
template DataFriendlyStruct(T) if (is(T==struct) && isPOD!T)
{
alias DataFriendlyStruct = ...
}
What exactly are you doing that such a micro optimization is
necessary?
It's just that i try to concrectly apply some things read in a
paper a few monthes ago. I won't be able to find the link again
but the idea is simple, here is a short summary:
structured types are dead, people gotta stup using classes and
structs. >They're not efficient.
That's not a scoop. Programs are slow because of that but struct
and class allow a complexity in the design that you can't reach
with globals.
The problem if you have global declarations of data everywhere
things become quickly super heavy, for example:
---
float[] effect1_filter_1_omega;
float[] effect1_filter_2_omega;
float[] effect2_filter_1_omega;
float[] effect2_filter_2_omega;
float[] voice1_osc1_phasemod_source1
float[] voice1_osc2_phasemod_source2
float[] voice2_osc1_phasemod_source1
float[] voice2_osc2_phasemod_source2
---
efficient to loop but imagine that we talking about 8
oscillators, 32 voices per oscillator, 2 effects per voice, etc...
so an abstraction is required to give a
"pseudo-structured-interface".
