Comments on: Optimizing away II

By: John

John — Sun, 31 May 2009 17:56:00 +0000

P.S. I’ll post the implementation of this code within a week or two.

By: John

John — Sun, 31 May 2009 17:54:59 +0000

How about this MSIL code?

ldloc.s error
ldloc.s p1
ldfld uint8 GenArt.Core.Classes.Pixel::R
ldloc.s p2
ldfld uint8 GenArt.Core.Classes.Pixel::R
sub
dup
mul
ldloc.s p1
ldfld uint8 GenArt.Core.Classes.Pixel::G
ldloc.s p2
ldfld uint8 GenArt.Core.Classes.Pixel::G
sub
dup
mul
ldloc.s p1
ldfld uint8 GenArt.Core.Classes.Pixel::B
ldloc.s p2
ldfld uint8 GenArt.Core.Classes.Pixel::B
sub
dup
mul
ldloc.s p1
ldfld uint8 GenArt.Core.Classes.Pixel::A
ldloc.s p2
ldfld uint8 GenArt.Core.Classes.Pixel::A
sub
dup
mul
add
add
add
add
ldloc.s p1
sizeof GenArt.Core.Classes.Pixel
add
stloc.s p1
ldloc.s p2
sizeof GenArt.Core.Classes.Pixel
add
stloc.s p2
stloc.s error

By: Yannickm

Yannickm — Tue, 24 Feb 2009 15:31:07 +0000

I am unsure how fast imul is nowadays, but wouldn’t using a lookup table be faster?

int sqrtLookup[256];

for( int i=0; i 0 ; i–, p1++, p2++ )
{
int r = p1->R – p2->R;
int g = p1->G – p2->G;
int b = p1->B – p2->B;
error += sqrtLookup[r] + sqrtLookup[g] + sqrtLookup[b];
}

By: Brian Low » EvoLisa Video

Brian Low » EvoLisa Video — Tue, 27 Jan 2009 03:35:48 +0000

[...] video was made using Roger’s source code modified with Dan Bystrom’s FitnessCalculator written in assembler. The program was changed to output a frame whenever the image improves by 5%. [...]

By: danbystrom

danbystrom — Thu, 01 Jan 2009 19:44:54 +0000

Problem solved: http://danbystrom.se/2009/01/01/optimizing-away-ii3/
The reason it worked for the default image I guess, is that it is rather dark and EvoLisa starts out with a black image. You probably used a much lighter image, which caused some significant bits to be truncated. Sorry for the inconvenience.

By: Optimizing away II.3 « Dan Byström’s Bwain

Optimizing away II.3 « Dan Byström’s Bwain — Thu, 01 Jan 2009 19:30:22 +0000

[...] Optimizing away II [...]

By: Otimizing away II.3 « Dan Byström’s Bwain

Otimizing away II.3 « Dan Byström’s Bwain — Thu, 01 Jan 2009 19:29:00 +0000

[...] Optimizing away II [...]

By: danbystrom

danbystrom — Wed, 31 Dec 2008 09:14:55 +0000

Since I haven’t even tried it on the default image I cannot decide if this is good or bad news…

How ’bout you zipping the thing and mail it to me and I’ll take a peek?

By: Nate Huddleson

Nate Huddleson — Tue, 30 Dec 2008 23:00:45 +0000

I tried to apply all of your optimizations (on an Intel box) and it works fine for the default image. However I am having trouble when I open my own image (a 300×300 jpg). In the end, I pulled out the NativeCode tweak, and it works fine now (for both). Strange…

By: Optimizing away II.2 « Dan Byström’s Bwain

Optimizing away II.2 « Dan Byström’s Bwain — Tue, 30 Dec 2008 13:21:39 +0000

[...] Optimizing away II [...]