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| author |  Rasmus Munk Larsen <rmlarsen@google.com> | 2016-10-04 15:09:11 -0700 |
|---|---|---|
| committer | Rasmus Munk Larsen <rmlarsen@google.com> | 2016-10-04 15:09:11 -0700 |
| commit | 7f67e6dfdb635ed1e744c0794bb1f3dd4306678f (patch) | |
| tree | 5d804948d2f5ef13054e79b3f765fcc460fcf5b2 /Eigen/src/Core/arch/AVX/MathFunctions.h | |
| parent | 765615609d40f485c718d60b76b35a277c36d5ce (diff) | |
Update comment for fast sqrt.
Diffstat (limited to 'Eigen/src/Core/arch/AVX/MathFunctions.h')
| -rw-r--r-- | Eigen/src/Core/arch/AVX/MathFunctions.h | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/Eigen/src/Core/arch/AVX/MathFunctions.h b/Eigen/src/Core/arch/AVX/MathFunctions.h index da70b6636..25cd992ef 100644 --- a/Eigen/src/Core/arch/AVX/MathFunctions.h +++ b/Eigen/src/Core/arch/AVX/MathFunctions.h @@ -355,9 +355,11 @@ pexp<Packet4d>(const Packet4d& _x) { // Functions for sqrt. // The EIGEN_FAST_MATH version uses the _mm_rsqrt_ps approximation and one step // of Newton's method, at a cost of 1-2 bits of precision as opposed to the -// exact solution. The main advantage of this approach is not just speed, but -// also the fact that it can be inlined and pipelined with other computations, -// further reducing its effective latency. +// exact solution. It does not handle +inf, or denormalized numbers correctly. +// The main advantage of this approach is not just speed, but also the fact that +// it can be inlined and pipelined with other computations, further reducing its +// effective latency. This is similar to Quake3's fast inverse square root. +// For detail see here: http://www.beyond3d.com/content/articles/8/ #if EIGEN_FAST_MATH template <> EIGEN_DEFINE_FUNCTION_ALLOWING_MULTIPLE_DEFINITIONS EIGEN_UNUSED Packet8f |