Make sure that psin/pcos return number in [-1,1] for large inputs (though sin/cos on large entries is quite useless because it's inaccurate)

This commit is contained in:
Gael Guennebaud
2018-12-23 16:13:24 +01:00
parent 5713fb7feb
commit 38d704def8
2 changed files with 22 additions and 0 deletions

View File

@@ -289,9 +289,15 @@ Packet psincos_float(const Packet& _x)
const Packet cst_coscof_p1 = pset1<Packet>(-1.388731625493765E-003f);
const Packet cst_coscof_p2 = pset1<Packet>( 4.166664568298827E-002f);
const Packet cst_cephes_FOPI = pset1<Packet>( 1.27323954473516f); // 4 / M_PI
const Packet cst_sincos_max_arg = pset1<Packet>( 13176795.0f); // Approx. (2**24) / (4/Pi).
Packet x = pabs(_x);
// Prevent sin/cos from generating values larger than 1.0 in magnitude
// for very large arguments by setting x to 0.0.
Packet small_or_nan_mask = pcmp_lt_or_nan(x, cst_sincos_max_arg);
x = pand(x, small_or_nan_mask);
// Scale x by 4/Pi to find x's octant.
Packet y = pmul(x, cst_cephes_FOPI);