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Fix a few confusing comments in psincos_float.

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This commit is contained in:
Rasmus Munk Larsen 2022-03-04 20:41:49 +00:00
parent f1b9692d63
commit 0e6f4e43f1
1 changed files with 3 additions and 3 deletions
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6
Eigen/src/Core/arch/Default/GenericPacketMathFunctions.h
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@ -603,13 +603,13 @@ Packet psincos_float(const Packet& _x)
// Scale x by 2/Pi to find x's octant.
Packet y = pmul(x, cst_2oPI);
// Rounding trick:
// Rounding trick to find nearest integer:
Packet y_round = padd(y, cst_rounding_magic);
EIGEN_OPTIMIZATION_BARRIER(y_round)
PacketI y_int = preinterpret<PacketI>(y_round); // last 23 digits represent integer (if abs(x)<2^24)
y = psub(y_round, cst_rounding_magic); // nearest integer to x*4/pi
y = psub(y_round, cst_rounding_magic); // nearest integer to x * (2/pi)
// Reduce x by y octants to get: -Pi/4 <= x <= +Pi/4
// Subtract y * Pi/2 to reduce x to the interval -Pi/4 <= x <= +Pi/4
// using "Extended precision modular arithmetic"
#if defined(EIGEN_HAS_SINGLE_INSTRUCTION_MADD)
// This version requires true FMA for high accuracy