On Oct 30, 2008, at 5:06 PM, Marc Feeley wrote:
Thanks Brad! The patch is not committed to the repository.
Do you mean "not" or "now"? I tried a "make update" on my linux box for testing and got
frying-pan:~/programs/gambc-v4_3_0-devel> make update D .hgignore D .hgtags Already on branch "master"
make
etc.
Note that your tests give slightly different results on my machine (as far as I can see probably only the least significant bit is different).
I reconfigured on my PPC G5 to not use the fused multiply-add instruction, i.e.,
[descartes:~/programs/gambc-v4_2_8] lucier% ./configure CC='gcc - mcpu=970 -m64 -mno-fused-madd'
and got the following differences myself. "new-results" are what I sent you before, "my-results are without the fused multiply-add instruction:
[descartes:~/programs/gambc-v4_2_8] lucier% diff new-results my- results 419c419
< -1.5707963267948966-0.i)
-1.5707963267948966-2.2737367544323206e-13i)421c421
< -1.5707963267948966-0.i)
-1.5707963267948966+2.2737367544323206e-13i)457c457
< .7853981633974483+363.1531368262252i)
.7853981633974483+363.15313682622525i)459c459
< .7853981633974483-363.1531368262252i)
.7853981633974483-363.15313682622525i)495c495
< -.7853981633974483+363.1531368262252i)
-.7853981633974483+363.15313682622525i)497c497
< -.7853981633974483-363.1531368262252i)
-.7853981633974483-363.15313682622525i)1051c1051
< 3295.836866004329-1.5707963267948966i)
3295.8368660043293-1.5707963267948966i)1053c1053
< -725.6131264718905+1.5707963267948966i)
-725.6131264718906+1.5707963267948966i)1055c1055
< -725.6131264718905-1.5707963267948966i)
-725.6131264718906-1.5707963267948966i)1438c1438
< 3295.836866004329+3.141592653589793i)
3295.8368660043293+3.141592653589793i)1476c1476
< -725.6131264718905)
-725.6131264718906)1514c1514
< -725.6131264718905+3.141592653589793i)
-725.6131264718906+3.141592653589793i)
So that accounts for a few of the differences. I hope we don't have to disable fused-madd on PPC, it speeds some things up a lot.
I believe that all the others are because of the following somewhat disheartening difference.
On my x86-64 linux box running Ubuntu 8.4:
frying-pan:~> gsi Gambit v4.3.0
(atan 1)
.7853981633974483
(sin (atan 1))
.7071067811865475
(cos (atan 1))
.7071067811865476
On my Mac G5 running 10.5.5:
[descartes:~/programs/gambc-v4_2_8] lucier% gsi/gsi Gambit v4.2.9
(atan 1)
.7853981633974483
(sin (atan 1))
.7071067811865476
(cos (atan 1))
.7071067811865475
Which one is correct, I don't know. Perhaps there's a double- rounding going on somewhere. (I'm glad I finally tracked this down.)
Brad