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authorNeil Fuller <nfuller@google.com>2014-10-01 11:55:10 +0100
committerNeil Fuller <nfuller@google.com>2014-10-01 14:04:15 +0100
commit33253a4baa6279f81a73425b49dfb6abe5f5416e (patch)
treec0077bd08ebc6f3c138a3b4ddb54a0ea1108b200 /test-runner
parent0451728645d559d904f579894d4b59e971e2369e (diff)
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Switch from FloatMath -> Math and Math.hypot where possible
The motivation is an API change: FloatMath is going to be deprecated and/or removed. Performance is not the goal of this change. That said... Math is faster than FloatMath with AOT compilation. While making the change, occurances of: {Float}Math.sqrt(x * x + y * y) and {Float}Math.sqrt({Float}Math.pow(x, 2) + {Float}Math.pow(y, 2)) have been replaced with: {(float)} Math.hypot(x, y) Right now there is no runtime intrinsic for hypot so is not faster in all cases for AOT compilation: Math.sqrt(x * x + y * y) is faster than Math.hypot(x, y) with AOT, but all other combinations of FloatMath, use of pow() etc. are slower than hypot(). hypot() has the advantage of being self documenting and could be optimized in future. None of the behavior differences around NaN and rounding appear to be important for the cases looked at: they all assume results and arguments are in range and usually the results are cast to float. Different implementations measured on hammerhead / L: AOT compiled: [FloatMath.hypot(x, y)] benchmark=Hypot_FloatMathHypot} 633.85 ns; σ=0.32 ns @ 3 trials [FloatMath.sqrt(x*x + y*y)] benchmark=Hypot_FloatMathSqrtMult} 684.17 ns; σ=4.83 ns @ 3 trials [FloatMath.sqrt(FloatMath.pow(x, 2) + FloatMath.pow(y, 2))] benchmark=Hypot_FloatMathSqrtPow} 1270.65 ns; σ=12.20 ns @ 6 trials [(float) Math.hypot(x, y)] benchmark=Hypot_MathHypot} 96.80 ns; σ=0.05 ns @ 3 trials [(float) Math.sqrt(x*x + y*y)] benchmark=Hypot_MathSqrtMult} 23.97 ns; σ=0.01 ns @ 3 trials [(float) Math.sqrt(Math.pow(x, 2) + Math.pow(y, 2))] benchmark=Hypot_MathSqrtPow} 156.19 ns; σ=0.12 ns @ 3 trials Interpreter: benchmark=Hypot_FloatMathHypot} 1180.54 ns; σ=5.13 ns @ 3 trials benchmark=Hypot_FloatMathSqrtMult} 1121.05 ns; σ=3.80 ns @ 3 trials benchmark=Hypot_FloatMathSqrtPow} 3327.14 ns; σ=7.33 ns @ 3 trials benchmark=Hypot_MathHypot} 856.57 ns; σ=1.41 ns @ 3 trials benchmark=Hypot_MathSqrtMult} 1028.92 ns; σ=9.11 ns @ 3 trials benchmark=Hypot_MathSqrtPow} 2539.47 ns; σ=24.44 ns @ 3 trials Bug: https://code.google.com/p/android/issues/detail?id=36199 Change-Id: I06c91f682095e627cb547d60d936ef87941be692
Diffstat (limited to 'test-runner')
-rw-r--r--test-runner/src/android/test/TouchUtils.java4
1 files changed, 2 insertions, 2 deletions
diff --git a/test-runner/src/android/test/TouchUtils.java b/test-runner/src/android/test/TouchUtils.java
index acbde0b..0fbffcd 100644
--- a/test-runner/src/android/test/TouchUtils.java
+++ b/test-runner/src/android/test/TouchUtils.java
@@ -576,7 +576,7 @@ public class TouchUtils {
final int fromX = xy[0];
final int fromY = xy[1];
- int distance = (int) Math.sqrt(deltaX * deltaX + deltaY * deltaY);
+ int distance = (int) Math.hypot(deltaX, deltaY);
drag(test, fromX, fromX + deltaX, fromY, fromY + deltaY, distance);
@@ -629,7 +629,7 @@ public class TouchUtils {
int deltaX = fromX - toX;
int deltaY = fromY - toY;
- int distance = (int)Math.sqrt(deltaX * deltaX + deltaY * deltaY);
+ int distance = (int)Math.hypot(deltaX, deltaY);
drag(test, fromX, toX, fromY, toY, distance);
return distance;