/* * CVS identifier: * * $Id: MathUtil.java,v 1.15 2001/09/14 08:48:51 grosbois Exp $ * * Class: MathUtil * * Description: Utility mathematical methods * * * * COPYRIGHT: * * This software module was originally developed by Raphaël Grosbois and * Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel * Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David * Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research * Centre France S.A) in the course of development of the JPEG2000 * standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This * software module is an implementation of a part of the JPEG 2000 * Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio * Systems AB and Canon Research Centre France S.A (collectively JJ2000 * Partners) agree not to assert against ISO/IEC and users of the JPEG * 2000 Standard (Users) any of their rights under the copyright, not * including other intellectual property rights, for this software module * with respect to the usage by ISO/IEC and Users of this software module * or modifications thereof for use in hardware or software products * claiming conformance to the JPEG 2000 Standard. Those intending to use * this software module in hardware or software products are advised that * their use may infringe existing patents. The original developers of * this software module, JJ2000 Partners and ISO/IEC assume no liability * for use of this software module or modifications thereof. No license * or right to this software module is granted for non JPEG 2000 Standard * conforming products. JJ2000 Partners have full right to use this * software module for his/her own purpose, assign or donate this * software module to any third party and to inhibit third parties from * using this software module for non JPEG 2000 Standard conforming * products. This copyright notice must be included in all copies or * derivative works of this software module. * * Copyright (c) 1999/2000 JJ2000 Partners. * */ using System; namespace CSJ2K.j2k.util { /// <summary> This class contains a collection of utility methods fro mathematical /// operations. All methods are static. /// /// </summary> public class MathUtil { /// <summary> Method that calculates the floor of the log, base 2, of 'x'. The /// calculation is performed in integer arithmetic, therefore, it is exact. /// /// </summary> /// <param name="x">The value to calculate log2 on. /// /// </param> /// <returns> floor(log(x)/log(2)), calculated in an exact way. /// /// </returns> public static int log2(int x) { int y, v; // No log of 0 or negative if (x <= 0) { throw new System.ArgumentException("" + x + " <= 0"); } // Calculate log2 (it's actually floor log2) v = x; y = - 1; while (v > 0) { v >>= 1; y++; } return y; } } }
Author: coder
Method that calculates the Greatest Common Divisor (GCD) of two positive integer numbers.
/*
* CVS identifier:
*
* $Id: MathUtil.java,v 1.15 2001/09/14 08:48:51 grosbois Exp $
*
* Class: MathUtil
*
* Description: Utility mathematical methods
*
*
*
* COPYRIGHT:
*
* This software module was originally developed by Raphaël Grosbois and
* Diego Santa Cruz (Swiss Federal Institute of Technology-EPFL); Joel
* Askelöf (Ericsson Radio Systems AB); and Bertrand Berthelot, David
* Bouchard, Félix Henry, Gerard Mozelle and Patrice Onno (Canon Research
* Centre France S.A) in the course of development of the JPEG2000
* standard as specified by ISO/IEC 15444 (JPEG 2000 Standard). This
* software module is an implementation of a part of the JPEG 2000
* Standard. Swiss Federal Institute of Technology-EPFL, Ericsson Radio
* Systems AB and Canon Research Centre France S.A (collectively JJ2000
* Partners) agree not to assert against ISO/IEC and users of the JPEG
* 2000 Standard (Users) any of their rights under the copyright, not
* including other intellectual property rights, for this software module
* with respect to the usage by ISO/IEC and Users of this software module
* or modifications thereof for use in hardware or software products
* claiming conformance to the JPEG 2000 Standard. Those intending to use
* this software module in hardware or software products are advised that
* their use may infringe existing patents. The original developers of
* this software module, JJ2000 Partners and ISO/IEC assume no liability
* for use of this software module or modifications thereof. No license
* or right to this software module is granted for non JPEG 2000 Standard
* conforming products. JJ2000 Partners have full right to use this
* software module for his/her own purpose, assign or donate this
* software module to any third party and to inhibit third parties from
* using this software module for non JPEG 2000 Standard conforming
* products. This copyright notice must be included in all copies or
* derivative works of this software module.
*
* Copyright (c) 1999/2000 JJ2000 Partners.
* */
using System;
namespace CSJ2K.j2k.util
{
///
/// operations. All methods are static.
///
///
public class MathUtil
{
///
/// positive integer numbers.
///
///
public static int gcd(int x1, int x2)
{
if (x1 < 0 || x2 < 0)
{
throw new System.ArgumentException("Cannot compute the GCD " + "if one integer is negative.");
}
int a, b, g, z;
if (x1 > x2)
{
a = x1;
b = x2;
}
else
{
a = x2;
b = x1;
}
if (b == 0)
return 0;
g = b;
while (g != 0)
{
z = a % g;
a = g;
g = z;
}
return a;
}
///
/// positive integer numbers.
///
///
/// Array containing the numbers.
///
///
public static int gcd(int[] x)
{
if (x.Length < 2)
{
throw new System.ApplicationException("Do not use this method if there are less than" + " two numbers.");
}
int tmp = gcd(x[x.Length - 1], x[x.Length - 2]);
for (int i = x.Length - 3; i >= 0; i–)
{
if (x[i] < 0)
{
throw new System.ArgumentException("Cannot compute the least " + "common multiple of " + "several numbers where " + "one, at least," + "is negative.");
}
tmp = gcd(tmp, x[i]);
}
return tmp;
}
}
}
[/csharp]
wraps the mod result to avoid negative results.
//http://isotopescreencapture.codeplex.com/ //The MIT License (MIT) namespace Isotope.Math { public static class MathUtil { /// <summary> /// This is a variant of mod that wraps the mod result to avoid negative results. this is what Python's mod operator does /// </summary> /// <param name="x"></param> /// <param name="y"></param> /// <returns></returns> private static double mod_wrap_angle(double x, double y) { if (y == 0) { throw new System.DivideByZeroException(); } double r = x%y; if (r > 0 && y < 0) { r = r + y; } else if (r < 0 && y > 0) { r = r + y; } return r; } /// <summary> /// wraps a number around so that it always fits between 0.0 and 1.0. negative numbers will wrap around to the correct positive number /// </summary> /// <remarks> /// if the input number is already in the range, no change will occur /// </remarks> /// <param name="v">input value </param> /// <returns>the wrapped number</returns> public static double WrapAngle_0_1(double v) { const double min = 0.0; const double max = 1.0; if (IsInRange(v, min, max)) { // the number is already in the range so do nothing return v; } return mod_wrap_angle(v, max); } /// <summary> /// Checks if a value is in a range (inclusive) /// </summary> /// <param name="val"></param> /// <param name="min"></param> /// <param name="max"></param> /// <returns></returns> public static bool IsInRange(double val, double min, double max) { return ((min <= val) && (val <= max)); } /// <summary> /// Checks if a value is in the range 0.0 to 1.0 inclusive /// </summary> /// <param name="val"></param> /// <returns></returns> public static bool IsInRange_0_1(double val) { return IsInRange(val, 0.0, 1.0); } } }
Normalise Angle
using System; public class MainClass{ public static double NormaliseAngle(double Angle) { return (Angle + 2 * Math.PI) % (2 * Math.PI); } }
Combines two input numbers in some proportion.
//http://isotopescreencapture.codeplex.com/ //The MIT License (MIT) namespace Isotope.Math { public static class MathUtil { /// <summary> /// Combines two input numbers in some proportion. /// ratio=0.0 the first number is not used at all, /// ratio=0.5 they are weight equally /// ratio=1.0 the first number completely dominates the value /// </summary> /// <param name="val0"></param> /// <param name="val1"></param> /// <param name="ratio"></param> /// <returns></returns> public static double Blend_0_1(double val0, double val1, double ratio) { var cratio = ClampToRange_0_1(ratio); var v0 = val0*cratio; var v1 = val1*(1.0 - cratio); return v0 + v1; } /// <summary> /// Given an input value will force the value to fit within the range (min,max) inclusive /// </summary> /// <param name="v"></param> /// <param name="min"></param> /// <param name="max"></param> /// <returns></returns> public static double ClampToRange(double v, double min, double max) { if (v < min) { v = min; } else if (v > max) { v = max; } return v; } /// <summary> /// Given an input value, will limit it to the range 0.0 and 1.0 inclusive /// </summary> /// <param name="v"></param> /// <returns>the clamped value</returns> public static double ClampToRange_0_1(double v) { return ClampToRange(v, 0.0, 1.0); } } }
rounds val to the nearest fractional value
//http://isotopescreencapture.codeplex.com/
//The MIT License (MIT)
namespace Isotope.Math
{
public static class MathUtil
{
public static double Round(double val, double snap_val)
{
return Round(val, System.MidpointRounding.AwayFromZero, snap_val);
}
///
///
/// the value tp round
/// what kind of rounding
/// round to this value (must be greater than 0.0)
///
public static double Round(double val, System.MidpointRounding rounding, double frac)
{
/*
if (frac <= 0)
{
throw new ArgumentOutOfRangeException("frac","must be greater than or equal to 0.0");
}*/
double retval = System.Math.Round((val/frac), rounding)*frac;
return retval;
}
public static double RoundUp(double v, double amount)
{
const System.MidpointRounding rounding = System.MidpointRounding.ToEven;
var result = Round(v + (amount/2.0), rounding, amount);
return result;
}
}
}
[/csharp]
Returns the minimum value of three numbers
//http://isotopescreencapture.codeplex.com/ //The MIT License (MIT) namespace Isotope.Math { public static class MathUtil { /// <summary> /// Returns the minimum value of three numbers /// </summary> /// <param name="a"></param> /// <param name="b"></param> /// <param name="c"></param> /// <returns></returns> public static double Min(double a, double b, double c) { return (System.Math.Min(System.Math.Min(a, b), c)); } } }