Back in the game: Numerics in D

[FeepingCreature]

On 20.02.2010 20:13, Norbert Nemec wrote:
> Hi there,
> 
> just to say "Hi" to those that might still remember my name from the
> good ol' times. (I just checked - I actually sent 464 messages to this
> list from 2004 to 2006 and none since.)
> 

I don't think I remember you! But I'll say welcome back anyway.

If you're interested in high-performance numerical computing, the current gdc has some hairy bugs that only show themselves on -O3 -ffast-math -march=native. Certainly enough to keep people on their toes :) Just keep it in mind - numerical errors may not actually be your fault.

Also, here's a copy of the GDC autovectorization patch: http://pastebin.com/f1c5b28df

It basically does the following: if you have a (simple) loop with index size four or two or whatever your mmx or sse step size is, it translates it into SSE expressions.

Example:

float[4] a, b, c; [...]

for (int i = 0; i < 4; ++i) a[i] = b[i] + c[i]; // addps

You can observe the process by passing -ftree-vectorizer-verbose=9 2>&1 |less to gdc (or gdc-build, which I've found handy for full custom rebuilds: http://pastebin.com/f28310a8a ).

Good luck with the numerical work and, welcome back to D. Have fun!