MathUtils.java

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package org.scotsbots.robotbase.utils;

/**
 * Has a collection of math functions and constants.
 * <br> Originally adapted from Adambots code.
 * @author Ben - Modified by Domenic
 */
public class MathUtils
{
	// // MATH CONSTANTS
	// --------------------------------------------------------

	public static final double TWO_PI = Math.PI * 2;
	public static final double PI_OVER_FOUR = Math.PI / 4;
	public static final double PI_OVER_TWO = Math.PI / 2;
	public static final double PI_OVER_180 = Math.PI / 180;
	public static final double PI_UNDER_180 = 180 / Math.PI;

	// // RANDOM VARIABLES
	// ------------------------------------------------------
	static long x = System.currentTimeMillis();
	static long y = System.currentTimeMillis() + 2065101653;
	static long z = System.currentTimeMillis() + 989498661;
	static long w = System.currentTimeMillis() + 626378301;
	static long v = System.currentTimeMillis() + 914577441;

	// // ROUNDING
	// --------------------------------------------------------------
	/**
	 * Rounds a double to a certain number of decimal places.
	 *
	 * @param n
	 *            The number to round.
	 * @param digit
	 *            10 to round to tens, 0.1 to round to tenths, etc.
	 * @return
	 */
	public static double roundTo(double n, double digit)
	{
		return Math.floor(n / digit + 0.5) * digit;
	}

	/**
	 * Rounds down a double to a certain number of decimal places.
	 *
	 * @param n
	 *            The number to round.
	 * @param digit
	 *            10 to round to tens, 0.1 to round to tenths, etc.
	 * @return
	 */
	public static double floorTo(double n, double digit)
	{
		return Math.floor(n / digit) * digit;
	}

	/**
	 * Rounds up a double to a certain number of decimal places.
	 *
	 * @param n
	 *            The number to round.
	 * @param digit
	 *            .1 to round to tens, 10 to round to tenths.
	 * @return
	 */
	public static double ceilTo(double n, double digit)
	{
		return Math.ceil(n / digit) * digit;
	}

	// // SIGN
	// ------------------------------------------------------------------
	/**
	 * 
	 * @param n
	 * @return- changes a double to it's opposite value
	 */
	public static double sign(double n)
	{
		return (n > 0.0) ? 1.0 : ((n < 0.0) ? -1.0 : 0.0);
	}
	/**
	 * 
	 * @param n
	 * @return- changes a float to it's opposite value
	 */
	public static float sign(float n)
	{
		return (n > 0.0f) ? 1.0f : ((n < 0.0f) ? -1.0f : 0.0f);
	}
	/**
	 * 
	 * @param n
	 * @return- changes an int to it's opposite value
	 */
	public static int sign(int n)
	{
		return (n > 0) ? 1 : ((n < 0) ? -1 : 0);
	}

	public static double exp(double x)
	{
		double s = 0;
		double a = 1;
		double[] r = { 1, 1, 2, 6, 24, 120, 720, 5040, 40320, 362880, 3628800 };
		for (int i = 0; i < r.length; i++)
		{
			s += a / r[i];
			a *= x;
		}
		return s;
	}

	// // RANDOM NUMBER GENERATOR
	// -----------------------------------------------
	/**
	 * 
	 * @param high
	 * @return- a generated random number 
	 */
	public static double rand(int high)
	{
		long t;
		t = (x ^ (x >> 7));
		x = y;
		y = z;
		z = w;
		w = v;
		v = (v ^ (v << 6)) ^ (t ^ (t << 13));
		return (Math.abs((y + y + 1) * v) % (20000 + Math.PI)) / (20000 + Math.PI) * high;
	}
}