FloatUtil.cs source code in C# .NET

Source code for the .NET framework in C#

                        
Code:

                         / 4.0 / 4.0 / untmp / DEVDIV_TFS / Dev10 / Releases / RTMRel / wpf / src / Shared / MS / Internal / FloatUtil.cs / 1305600 / FloatUtil.cs
                        

                        
                            //---------------------------------------------------------------------------- 
//
// Copyright (C) Microsoft Corporation.  All rights reserved.
//
// File: FloatUtil.cs 
//
// Description: This file contains the implementation of FloatUtil, which 
//              provides "fuzzy" comparison functionality for floats and 
//              float-based classes and structs in our code.
// 
// History:
//  04/28/2003 : [....] - Created this header
//  05/20/2003 : [....] - Move to Shared.
// 
//---------------------------------------------------------------------------
 
using System; 

namespace MS.Internal 
{
    internal static class FloatUtil
    {
        internal static float FLT_EPSILON  =   1.192092896e-07F; 
        internal static float FLT_MAX_PRECISION = 0xffffff;
        internal static float INVERSE_FLT_MAX_PRECISION = 1.0F / FLT_MAX_PRECISION; 
 
        /// 
        /// AreClose 
        /// 
        public static bool AreClose(float a, float b)
        {
            if(a == b) return true; 
            // This computes (|a-b| / (|a| + |b| + 10.0f)) < FLT_EPSILON
            float eps = ((float)Math.Abs(a) + (float)Math.Abs(b) + 10.0f) * FLT_EPSILON; 
            float delta = a - b; 
            return(-eps < delta) && (eps > delta);
        } 

        /// 
        /// IsOne
        ///  
        public static bool IsOne(float a)
        { 
            return (float)Math.Abs(a-1.0f) < 10.0f * FLT_EPSILON; 
        }
 
        /// 
        /// IsZero
        /// 
        public static bool IsZero(float a) 
        {
            return (float)Math.Abs(a) < 10.0f * FLT_EPSILON; 
        } 

        ///  
        /// IsCloseToDivideByZero
        /// 
        public static bool IsCloseToDivideByZero(float numerator, float denominator)
        { 
            // When updating this, please also update code in Arithmetic.h
            return Math.Abs(denominator) <= Math.Abs(numerator) * INVERSE_FLT_MAX_PRECISION; 
        } 

    } 
}

// File provided for Reference Use Only by Microsoft Corporation (c) 2007.
// Copyright (c) Microsoft Corporation. All rights reserved.

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