-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On Wednesday, 2013-04-10 at 01:20 -0300, Claudio Freire wrote:
Actually, the OP links show that it's not that they're "innaccurate" per-se, it's stated on the IA docs (and I do remember reading that, though I didn't find it now when I re-checked) that it's designed to be used within the -Pi/2..Pi/2 range, and using the instructions outside the range would yield less precise results, that reduction to that range ought to be done in software, with the aid of fprem.
Ah, that makes sense.
Now, not sure what did libm does, but the "fast and wrong" version didn't even call fprem, so I guess the slowdown could come from it (since it has to be invoked in a loop). If not, using fprem may be much faster than invoking libm.
I guess this could be testing by calling sincos(fmod(x, M_PI)) on the old, inaccurate gcc version, and checking the result.
In the forum thread I mentioned at the start there are some posts listing other math libraries, some commercial, that give better results. But it needs rebuild of the affected applications, of course. - -- Cheers, Carlos E. R. (from 12.1 x86_64 "Asparagus" at Telcontar) -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.18 (GNU/Linux) iEYEARECAAYFAlFlMp0ACgkQtTMYHG2NR9VwKQCdHL0Sx0KpRJzydOiQO1soLizg ze8AnRppHYPZTx+919VvrmDwaWsCpnBi =C0eO -----END PGP SIGNATURE----- -- To unsubscribe, e-mail: opensuse-factory+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse-factory+owner@opensuse.org