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Former-commit-id: ad694de554cb1cbec984f5af7abde6885649b2cc Former-commit-id: 7d411118b462d6451d386c6915c6d31ddc7289c8 Former-commit-id: dd60d42bb56b148f630bd1ad3d7af8e5e9bb5764pull/1/head
4 changed files with 494 additions and 378 deletions
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// <copyright file="Rational.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageProcessorCore |
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{ |
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using System; |
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using System.Text; |
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internal struct BigRational : IEquatable<BigRational> |
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{ |
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private bool IsIndeterminate |
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{ |
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get |
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{ |
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if (Denominator != 0) |
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return false; |
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return Numerator == 0; |
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} |
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} |
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private bool IsInteger => Denominator == 1; |
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private bool IsNegativeInfinity |
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{ |
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get |
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{ |
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if (Denominator != 0) |
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return false; |
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return Numerator == -1; |
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} |
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} |
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private bool IsPositiveInfinity |
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{ |
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get |
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{ |
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if (Denominator != 0) |
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return false; |
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return Numerator == 1; |
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} |
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} |
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private bool IsZero |
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{ |
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get |
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{ |
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if (Denominator != 1) |
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return false; |
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return Numerator == 0; |
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} |
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} |
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private static long GreatestCommonDivisor(long a, long b) |
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{ |
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return b == 0 ? a : GreatestCommonDivisor(b, a % b); |
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} |
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private void Simplify() |
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{ |
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if (IsIndeterminate) |
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return; |
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if (IsNegativeInfinity) |
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return; |
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if (IsPositiveInfinity) |
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return; |
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if (IsInteger) |
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return; |
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if (IsZero) |
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return; |
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if (Numerator == 0) |
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{ |
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Denominator = 0; |
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return; |
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} |
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if (Numerator == Denominator) |
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{ |
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Numerator = 1; |
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Denominator = 1; |
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} |
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long gcd = GreatestCommonDivisor(Math.Abs(Numerator), Math.Abs(Denominator)); |
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if (gcd > 1) |
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{ |
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Numerator = Numerator / gcd; |
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Denominator = Denominator / gcd; |
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} |
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} |
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public BigRational(long numerator, long denominator) |
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: this(numerator, denominator, false) |
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{ |
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} |
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public BigRational(long numerator, long denominator, bool simplify) |
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{ |
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Numerator = numerator; |
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Denominator = denominator; |
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if (simplify) |
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Simplify(); |
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} |
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public BigRational(double value, bool bestPrecision) |
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{ |
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if (double.IsNaN(value)) |
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{ |
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Numerator = Denominator = 0; |
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return; |
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} |
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if (double.IsPositiveInfinity(value)) |
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{ |
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Numerator = 1; |
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Denominator = 0; |
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return; |
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} |
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if (double.IsNegativeInfinity(value)) |
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{ |
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Numerator = -1; |
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Denominator = 0; |
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return; |
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} |
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Numerator = 1; |
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Denominator = 1; |
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double val = Math.Abs(value); |
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double df = Numerator / (double)Denominator; |
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double epsilon = bestPrecision ? double.Epsilon : .000001; |
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while (Math.Abs(df - val) > epsilon) |
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{ |
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if (df < val) |
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Numerator++; |
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else |
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{ |
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Denominator++; |
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Numerator = (int)(val * Denominator); |
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} |
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df = Numerator / (double)Denominator; |
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} |
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if (value < 0.0) |
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Numerator *= -1; |
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Simplify(); |
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} |
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public long Denominator |
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{ |
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get; |
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private set; |
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} |
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public long Numerator |
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{ |
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get; |
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private set; |
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} |
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public bool Equals(BigRational other) |
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{ |
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if (Denominator == other.Denominator) |
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return Numerator == other.Numerator; |
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if (Numerator == 0 && Denominator == 0) |
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return other.Numerator == 0 && other.Denominator == 0; |
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if (other.Numerator == 0 && other.Denominator == 0) |
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return Numerator == 0 && Denominator == 0; |
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return (Numerator * other.Denominator) == (Denominator * other.Numerator); |
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} |
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public override int GetHashCode() |
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{ |
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return ((Numerator * 397) ^ Denominator).GetHashCode(); |
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} |
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public string ToString(IFormatProvider provider) |
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{ |
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if (IsIndeterminate) |
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return "[ Indeterminate ]"; |
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if (IsPositiveInfinity) |
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return "[ PositiveInfinity ]"; |
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if (IsNegativeInfinity) |
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return "[ NegativeInfinity ]"; |
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if (IsZero) |
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return "0"; |
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if (IsInteger) |
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return Numerator.ToString(provider); |
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StringBuilder sb = new StringBuilder(); |
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sb.Append(Numerator.ToString(provider)); |
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sb.Append("/"); |
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sb.Append(Denominator.ToString(provider)); |
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return sb.ToString(); |
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} |
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} |
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} |
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@ -0,0 +1,355 @@ |
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// <copyright file="LongRational.cs" company="James Jackson-South">
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// Copyright (c) James Jackson-South and contributors.
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// Licensed under the Apache License, Version 2.0.
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// </copyright>
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namespace ImageProcessorCore |
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{ |
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using System; |
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using System.Globalization; |
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using System.Text; |
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/// <summary>
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/// Represents a number that can be expressed as a fraction
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/// </summary>
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/// <remarks>
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/// This is a very simplified implementation of a rational number designed for use with metadata only.
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/// </remarks>
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internal struct LongRational : IEquatable<LongRational> |
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{ |
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/// <summary>
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/// Initializes a new instance of the <see cref="LongRational"/> struct.
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/// </summary>
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/// <param name="numerator">
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/// The number above the line in a vulgar fraction showing how many of the parts
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/// indicated by the denominator are taken.
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/// </param>
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/// <param name="denominator">
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/// The number below the line in a vulgar fraction; a divisor.
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/// </param>
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public LongRational(long numerator, long denominator) |
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: this(numerator, denominator, false) |
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{ |
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} |
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/// <summary>
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/// Initializes a new instance of the <see cref="LongRational"/> struct.
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/// </summary>
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/// <param name="numerator">
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/// The number above the line in a vulgar fraction showing how many of the parts
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/// indicated by the denominator are taken.
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/// </param>
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/// <param name="denominator">
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/// The number below the line in a vulgar fraction; a divisor.
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/// </param>
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/// <param name="simplify">
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/// Whether to attempt to simplify the fractional parts.
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/// </param>
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public LongRational(long numerator, long denominator, bool simplify) |
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: this() |
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{ |
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this.Numerator = numerator; |
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this.Denominator = denominator; |
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if (simplify) |
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{ |
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this.Simplify(); |
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} |
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} |
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/// <summary>
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/// Initializes a new instance of the <see cref="LongRational"/> struct.
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/// </summary>
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/// <param name="value">The <see cref="double"/> to create the instance from.</param>
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/// <param name="bestPrecision">Whether to use the best possible precision when parsing the value.</param>
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public LongRational(double value, bool bestPrecision) |
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: this() |
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{ |
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if (double.IsNaN(value)) |
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{ |
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this.Numerator = this.Denominator = 0; |
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return; |
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} |
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if (double.IsPositiveInfinity(value)) |
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{ |
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this.Numerator = 1; |
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this.Denominator = 0; |
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return; |
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} |
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if (double.IsNegativeInfinity(value)) |
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{ |
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this.Numerator = -1; |
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this.Denominator = 0; |
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return; |
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} |
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this.Numerator = 1; |
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this.Denominator = 1; |
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double val = Math.Abs(value); |
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double df = this.Numerator / (double)this.Denominator; |
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double epsilon = bestPrecision ? double.Epsilon : .000001; |
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while (Math.Abs(df - val) > epsilon) |
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{ |
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if (df < val) |
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{ |
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this.Numerator++; |
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} |
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else |
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{ |
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this.Denominator++; |
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this.Numerator = (int)(val * this.Denominator); |
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} |
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df = this.Numerator / (double)this.Denominator; |
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} |
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if (value < 0.0) |
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{ |
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this.Numerator *= -1; |
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} |
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this.Simplify(); |
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} |
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/// <summary>
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/// Gets the numerator of a number.
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/// </summary>
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public long Numerator |
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{ |
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get; |
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private set; |
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} |
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/// <summary>
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/// Gets the denominator of a number.
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/// </summary>
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public long Denominator |
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{ |
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get; |
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private set; |
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} |
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/// <summary>
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/// Gets a value indicating whether this instance is indeterminate.
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/// </summary>
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public bool IsIndeterminate |
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{ |
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get |
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{ |
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if (this.Denominator != 0) |
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{ |
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return false; |
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} |
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return this.Numerator == 0; |
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} |
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} |
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/// <summary>
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/// Gets a value indicating whether this instance is an integer (n, 1)
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/// </summary>
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public bool IsInteger => this.Denominator == 1; |
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/// <summary>
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/// Gets a value indicating whether this instance is equal to negative infinity (-1, 0)
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/// </summary>
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public bool IsNegativeInfinity |
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{ |
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get |
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{ |
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if (this.Denominator != 0) |
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{ |
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return false; |
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} |
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return this.Numerator == -1; |
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} |
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} |
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/// <summary>
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/// Gets a value indicating whether this instance is equal to positive infinity (1, 0)
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/// </summary>
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public bool IsPositiveInfinity |
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{ |
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get |
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{ |
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if (this.Denominator != 0) |
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{ |
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return false; |
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} |
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return this.Numerator == 1; |
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} |
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} |
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/// <summary>
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/// Gets a value indicating whether this instance is equal to 0 (0, 1)
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/// </summary>
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public bool IsZero |
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{ |
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get |
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{ |
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if (this.Denominator != 1) |
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{ |
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return false; |
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} |
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return this.Numerator == 0; |
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} |
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} |
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/// <inheritdoc/>
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public bool Equals(LongRational other) |
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{ |
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if (this.Denominator == other.Denominator) |
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{ |
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return this.Numerator == other.Numerator; |
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} |
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if (this.Numerator == 0 && this.Denominator == 0) |
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{ |
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return other.Numerator == 0 && other.Denominator == 0; |
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} |
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if (other.Numerator == 0 && other.Denominator == 0) |
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{ |
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return this.Numerator == 0 && this.Denominator == 0; |
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} |
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return (this.Numerator * other.Denominator) == (this.Denominator * other.Numerator); |
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} |
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/// <inheritdoc/>
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public override int GetHashCode() |
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{ |
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return this.GetHashCode(this); |
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} |
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/// <inheritdoc/>
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public override string ToString() |
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{ |
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return this.ToString(CultureInfo.InvariantCulture); |
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} |
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/// <summary>
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/// Converts the numeric value of this instance to its equivalent string representation using
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/// the specified culture-specific format information.
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/// </summary>
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/// <param name="provider">
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/// An object that supplies culture-specific formatting information.
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/// </param>
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/// <returns>The <see cref="string"/></returns>
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public string ToString(IFormatProvider provider) |
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{ |
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if (this.IsIndeterminate) |
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{ |
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return "[ Indeterminate ]"; |
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} |
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if (this.IsPositiveInfinity) |
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{ |
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return "[ PositiveInfinity ]"; |
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} |
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if (this.IsNegativeInfinity) |
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{ |
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return "[ NegativeInfinity ]"; |
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} |
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if (this.IsZero) |
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{ |
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return "0"; |
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} |
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if (this.IsInteger) |
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{ |
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return this.Numerator.ToString(provider); |
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} |
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StringBuilder sb = new StringBuilder(); |
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sb.Append(this.Numerator.ToString("R", provider)); |
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sb.Append("/"); |
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sb.Append(this.Denominator.ToString("R", provider)); |
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return sb.ToString(); |
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} |
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/// <summary>
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/// Finds the greatest common divisor of two <see cref="long"/> values.
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/// </summary>
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/// <param name="left">The first value</param>
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/// <param name="right">The second value</param>
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/// <returns>The <see cref="long"/></returns>
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private static long GreatestCommonDivisor(long left, long right) |
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{ |
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return right == 0 ? left : GreatestCommonDivisor(right, left % right); |
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} |
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/// <summary>
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/// Simplifies the <see cref="LongRational"/>
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/// </summary>
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private void Simplify() |
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{ |
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if (this.IsIndeterminate) |
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{ |
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return; |
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} |
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if (this.IsNegativeInfinity) |
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{ |
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return; |
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} |
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if (this.IsPositiveInfinity) |
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{ |
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return; |
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} |
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if (this.IsInteger) |
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|
{ |
||||
|
return; |
||||
|
} |
||||
|
|
||||
|
if (this.IsZero) |
||||
|
{ |
||||
|
return; |
||||
|
} |
||||
|
|
||||
|
if (this.Numerator == 0) |
||||
|
{ |
||||
|
this.Denominator = 0; |
||||
|
return; |
||||
|
} |
||||
|
|
||||
|
if (this.Numerator == this.Denominator) |
||||
|
{ |
||||
|
this.Numerator = 1; |
||||
|
this.Denominator = 1; |
||||
|
} |
||||
|
|
||||
|
long gcd = GreatestCommonDivisor(Math.Abs(this.Numerator), Math.Abs(this.Denominator)); |
||||
|
if (gcd > 1) |
||||
|
{ |
||||
|
this.Numerator = this.Numerator / gcd; |
||||
|
this.Denominator = this.Denominator / gcd; |
||||
|
} |
||||
|
} |
||||
|
|
||||
|
/// <summary>
|
||||
|
/// Returns the hash code for this instance.
|
||||
|
/// </summary>
|
||||
|
/// <param name="rational">
|
||||
|
/// The instance of <see cref="LongRational"/> to return the hash code for.
|
||||
|
/// </param>
|
||||
|
/// <returns>
|
||||
|
/// A 32-bit signed integer that is the hash code for this instance.
|
||||
|
/// </returns>
|
||||
|
private int GetHashCode(LongRational rational) |
||||
|
{ |
||||
|
return ((rational.Numerator * 397) ^ rational.Denominator).GetHashCode(); |
||||
|
} |
||||
|
} |
||||
|
} |
||||
Loading…
Reference in new issue