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The testbed for JBox2D, a 2d java physics engine, ported from the C++ Box2d engine.
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/*******************************************************************************
* Copyright (c) 2013, Daniel Murphy
* All rights reserved.
*
* Redistribution and use in source and binary forms, with or without modification,
* are permitted provided that the following conditions are met:
* * Redistributions of source code must retain the above copyright notice,
* this list of conditions and the following disclaimer.
* * Redistributions in binary form must reproduce the above copyright notice,
* this list of conditions and the following disclaimer in the documentation
* and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
* IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
* INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
* POSSIBILITY OF SUCH DAMAGE.
******************************************************************************/
package org.jbox2d.tests.math;
import org.jbox2d.common.MathUtils;
public class SinCosTest {
// formating stuff
public static final int COLUMN_PADDING = 3;
public static final int NUM_DECIMALS = 8;
public static int numTables = 50;
// accuracy
public static float mostPreciseTable = .00001f;
public static float leastPreciseTable = .01f;
public static int accuracyIterations = 100000;
// speed
public static int speedTrials = 20;
public static int speedIterations = 50000;
private static SinCosTable[] tables;
/**
* @param args
*/
public static void main(String[] args) {
int overall = 1;
try {
numTables = Integer.parseInt(args[0]);
mostPreciseTable = Float.parseFloat(args[1]);
leastPreciseTable = Float.parseFloat(args[2]);
accuracyIterations = Integer.parseInt(args[3]);
speedTrials = Integer.parseInt(args[4]);
speedIterations = Integer.parseInt(args[5]);
overall = Integer.parseInt(args[6]);
} catch (Exception e) {
System.out
.println("Parameters: "
+ " "
+ " ");
System.out.println("Sample parameters: 200 .00001 .01 100000 20 5000 2");
// return;
}
System.out.println("Tables: " + numTables);
System.out.println("Most Precise Table: " + mostPreciseTable);
System.out.println("Least Precise Table: " + leastPreciseTable);
System.out.println("Accuracy Iterations: " + accuracyIterations);
System.out.println("Speed Trials: " + speedTrials);
System.out.println("Speed Iterations: " + speedIterations);
constructTables();
doAccuracyTest(true);
for (int i = 0; i < overall; i++) {
doSpeedTest(true);
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
/**
* constructs the tables from the static parameters
*/
public static final void constructTables() {
tables = new SinCosTable[numTables];
System.out.println("constructing tables");
for (int i = 0; i < numTables; i++) {
// well... basic lerp
float precision = i * 1f / numTables * (leastPreciseTable - mostPreciseTable)
+ mostPreciseTable;
tables[i] = new SinCosTable(precision);
}
}
/**
* accuracy test from the static parameters, the tables array needs to be constructed as well,
* returns double[tables][0-3 (no lerp, lerp, then the difference)]
*
* @return
*/
public static final double[][] doAccuracyTest(boolean print) {
System.out.println("doing accuracy tests");
double[][] accuracyResults = new double[numTables][3];
SinCosTable.LERP_LOOKUP = false;
// without lerp
for (int i = 0; i < numTables; i++) {
accuracyResults[i][0] = accuracyTest(tables[i], accuracyIterations);
}
SinCosTable.LERP_LOOKUP = true;
// with lerp
for (int i = 0; i < numTables; i++) {
accuracyResults[i][1] = accuracyTest(tables[i], accuracyIterations);
}
for (int i = 0; i < numTables; i++) {
accuracyResults[i][2] = accuracyResults[i][0] - accuracyResults[i][1];
}
if (print) {
System.out.println("Accuracy results, average displacement");
String header[] = { "Not lerped", "Lerped", "Difference" };
String side[] = new String[numTables + 1];
side[0] = "Table precision";
for (int i = 0; i < tables.length; i++) {
side[i + 1] = formatDecimal(tables[i].precision, NUM_DECIMALS);
}
printTable(header, side, accuracyResults);
}
return accuracyResults;
}
/**
* speed test from the static parameters the tables array needs to be constructed as well, returns
* double[tables][0-3 (no lerp, lerp, then the difference)]
*
* @return
*/
public static final double[][] doSpeedTest(boolean print) {
System.out.println("\nDoing speed tests");
double[][] speedResults = new double[numTables][4];
SinCosTable.LERP_LOOKUP = false;
// without lerp
for (int i = 0; i < numTables; i++) {
speedResults[i][0] = speedTest(tables[i], speedIterations, speedTrials);
}
SinCosTable.LERP_LOOKUP = true;
// with lerp
for (int i = 0; i < numTables; i++) {
speedResults[i][1] = speedTest(tables[i], speedIterations, speedTrials);
}
// with the Math calls
for (int i = 0; i < numTables; i++) {
speedResults[i][3] = speedTestMath(speedIterations, speedTrials);
}
for (int i = 0; i < numTables; i++) {
speedResults[i][2] = speedResults[i][0] - speedResults[i][1];
}
if (print) {
System.out.println("Speed results, in iterations per second (higher number means faster)");
String header[] = { "Not lerped", "Lerped", "Difference", "Java Math" };
String side[] = new String[numTables + 1];
side[0] = "Table precision";
for (int i = 0; i < tables.length; i++) {
side[i + 1] = formatDecimal(tables[i].precision, NUM_DECIMALS);
}
printTable(header, side, speedResults);
}
return speedResults;
}
private static double accuracyTest(SinCosTable table, int iterations) {
double totalDiff = 0f, diff = 0f;
for (int i = 0; i < iterations; i++) {
float querry = (float) Math.random() * MathUtils.TWOPI;
diff = MathUtils.abs((float) Math.sin(querry) - table.sin(querry));
totalDiff += diff;
}
totalDiff /= iterations;
return totalDiff;
}
private static void printTable(String header[], String side[], double[][] results) {
// first determine the amount of space we need for each column
int[] colLengths = new int[results[0].length + 1];
for (int i = 0; i < colLengths.length; i++) {
colLengths[i] = 0;
}
for (int j = -1; j < results[0].length; j++) {
if (j == -1) {
int colLength = side[j + 1].length() + COLUMN_PADDING;
if (colLength > colLengths[j + 1]) {
colLengths[j + 1] = colLength;
}
} else {
int colLength = header[j].length() + COLUMN_PADDING;
if (colLength > colLengths[j + 1]) {
colLengths[j + 1] = colLength;
}
for (int i = 0; i < results.length; i++) {
colLength = (formatDecimal(results[i][j], NUM_DECIMALS)).length() + COLUMN_PADDING;
if (colLength > colLengths[j + 1]) {
colLengths[j + 1] = colLength;
}
}
}
}
// header
System.out.print(spaceString(side[0], colLengths[0]));
for (int i = 1; i < colLengths.length; i++) {
System.out.print(spaceString(header[i - 1], colLengths[i]));
}
System.out.println();
for (int i = 0; i < results.length; i++) {
for (int j = -1; j < results[i].length; j++) {
if (j == -1) {
System.out.print(spaceString(side[i + 1], colLengths[j + 1]));
} else {
String toPrint = formatDecimal(results[i][j], NUM_DECIMALS);
System.out.print(spaceString(toPrint, colLengths[j + 1]));
}
}
System.out.println();
}
}
private static long speedTest(SinCosTable table, final int numIterations, final int numTrials) {
long startTime, endTime;
long totalTime = 0;
float i, j;
float k = 0;
final float jstep = MathUtils.TWOPI / numIterations;
for (i = 0; i < numTrials; i++) {
startTime = System.nanoTime();
for (j = 0; j < MathUtils.TWOPI; j += jstep) {
k += table.sin(j);
}
endTime = System.nanoTime();
totalTime += endTime - startTime;
}
i += k;
return numIterations * numTrials * 1000000000l / (totalTime);
}
private static long speedTestMath(final int numIterations, final int numTrials) {
long startTime, endTime;
long totalTime = 0;
float i, j;
float k = 0;
final float jstep = MathUtils.TWOPI / numIterations;
for (i = 0; i < numTrials; i++) {
startTime = System.nanoTime();
for (j = 0; j < MathUtils.TWOPI; j += jstep) {
k += (float) StrictMath.sin(j);
}
endTime = System.nanoTime();
totalTime += endTime - startTime;
}
i += k;
return numIterations * numTrials * 1000000000l / (totalTime);
}
private static String spaceString(String str, int space) {
// if the string is more than the space
if (str.length() == space) {
return str;
} else if (str.length() >= space) {
return str.substring(0, space);
}
String s = new String(str);
for (int i = s.length(); i < space; i++) {
s = " " + s;
}
return s;
}
private static String formatDecimal(double n, int decimals) {
String num = n + "";
// no decimal
if (num.indexOf(".") == -1) {
return num;
}
boolean ePresent = false;
String e = null;
if (num.indexOf("E") != -1) {
e = num.substring(num.indexOf("E"));
decimals -= e.length();
num = num.substring(0, num.indexOf("E"));
ePresent = true;
}
int decLen = num.substring(num.indexOf(".") + 1).length();
int numLen = num.substring(0, num.indexOf(".")).length();
// if not enough decimals
if (decLen < decimals) {
for (int i = 0; i < (decimals - decLen); i++) {
num = num + " ";
}
} else if (decLen > decimals) { // more decimals than needed
num = num.substring(0, numLen + decimals + 1);
}
if (ePresent) {
num += e;
}
return num;
}
}
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