On 09/11/17 15:02, Laurent Bourgès wrote: > --- testing cbrt(double) = pow(double, 1/3) --- > Loop on Math.pow(double, 1/3), args in [-10.0,10.0], took 0.739 s > Loop on FastMath.cbrt(double), args in [-10.0,10.0], took 0.166 s > Loop on Math.pow(double, 1/3), args in [-0.7,0.7], took 0.746 s > Loop on FastMath.cbrt(double), args in [-0.7,0.7], took 0.166 s > Loop on Math.pow(double, 1/3), args in [-0.1,0.1], took 0.742 s > Loop on FastMath.cbrt(double), args in [-0.1,0.1], took 0.165 s > Loop on Math.pow(double, 1/3), args in all magnitudes, took 0.753 s > Loop on FastMath.cbrt(double), args in all magnitudes, took 0.244 > > Conclusion: > - acos / asin / atan functions are quite slow: it confirms these are not > optimized by hotspot intrinsics. > > - cbrt() is slower than sqrt() : 1.1s vs 0.1 => 10x slower > - cbrt() is slower than pow(1/3) : 1.1s vs 0.7s => 50% slower
No. cbrt() is faster than pow(1/3) : 0.24 vs 0.75 -- Andrew Haley Java Platform Lead Engineer Red Hat UK Ltd. <https://www.redhat.com> EAC8 43EB D3EF DB98 CC77 2FAD A5CD 6035 332F A671
