Neil Fuller 33253a4baa 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
2014-10-01 14:04:15 +01:00

162 lines
3.9 KiB
Java

/*
* Copyright (C) 2007 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.graphics;
import android.os.Parcel;
import android.os.Parcelable;
/**
* PointF holds two float coordinates
*/
public class PointF implements Parcelable {
public float x;
public float y;
public PointF() {}
public PointF(float x, float y) {
this.x = x;
this.y = y;
}
public PointF(Point p) {
this.x = p.x;
this.y = p.y;
}
/**
* Set the point's x and y coordinates
*/
public final void set(float x, float y) {
this.x = x;
this.y = y;
}
/**
* Set the point's x and y coordinates to the coordinates of p
*/
public final void set(PointF p) {
this.x = p.x;
this.y = p.y;
}
public final void negate() {
x = -x;
y = -y;
}
public final void offset(float dx, float dy) {
x += dx;
y += dy;
}
/**
* Returns true if the point's coordinates equal (x,y)
*/
public final boolean equals(float x, float y) {
return this.x == x && this.y == y;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
PointF pointF = (PointF) o;
if (Float.compare(pointF.x, x) != 0) return false;
if (Float.compare(pointF.y, y) != 0) return false;
return true;
}
@Override
public int hashCode() {
int result = (x != +0.0f ? Float.floatToIntBits(x) : 0);
result = 31 * result + (y != +0.0f ? Float.floatToIntBits(y) : 0);
return result;
}
@Override
public String toString() {
return "PointF(" + x + ", " + y + ")";
}
/**
* Return the euclidian distance from (0,0) to the point
*/
public final float length() {
return length(x, y);
}
/**
* Returns the euclidian distance from (0,0) to (x,y)
*/
public static float length(float x, float y) {
return (float) Math.hypot(x, y);
}
/**
* Parcelable interface methods
*/
@Override
public int describeContents() {
return 0;
}
/**
* Write this point to the specified parcel. To restore a point from
* a parcel, use readFromParcel()
* @param out The parcel to write the point's coordinates into
*/
@Override
public void writeToParcel(Parcel out, int flags) {
out.writeFloat(x);
out.writeFloat(y);
}
public static final Parcelable.Creator<PointF> CREATOR = new Parcelable.Creator<PointF>() {
/**
* Return a new point from the data in the specified parcel.
*/
public PointF createFromParcel(Parcel in) {
PointF r = new PointF();
r.readFromParcel(in);
return r;
}
/**
* Return an array of rectangles of the specified size.
*/
public PointF[] newArray(int size) {
return new PointF[size];
}
};
/**
* Set the point's coordinates from the data stored in the specified
* parcel. To write a point to a parcel, call writeToParcel().
*
* @param in The parcel to read the point's coordinates from
*/
public void readFromParcel(Parcel in) {
x = in.readFloat();
y = in.readFloat();
}
}