[12292] | 1 | #region License Information
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| 2 | /* HeuristicLab
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[16057] | 3 | * Copyright (C) 2002-2018 Heuristic and Evolutionary Algorithms Laboratory (HEAL)
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[12292] | 4 | *
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| 5 | * This file is part of HeuristicLab.
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| 6 | *
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| 7 | * HeuristicLab is free software: you can redistribute it and/or modify
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| 8 | * it under the terms of the GNU General Public License as published by
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| 9 | * the Free Software Foundation, either version 3 of the License, or
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| 10 | * (at your option) any later version.
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| 11 | *
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| 12 | * HeuristicLab is distributed in the hope that it will be useful,
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| 13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of
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| 14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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| 15 | * GNU General Public License for more details.
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| 16 | *
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| 17 | * You should have received a copy of the GNU General Public License
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| 18 | * along with HeuristicLab. If not, see <http://www.gnu.org/licenses/>.
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| 19 | */
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| 20 | #endregion
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| 21 |
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| 22 | using System;
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| 23 | using System.Collections.Generic;
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| 24 | using System.Linq;
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| 25 |
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| 26 | namespace HeuristicLab.Common {
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| 27 | public static class SequenceGenerator {
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| 28 | /// <summary>
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| 29 | /// Generates a sequence of evenly spaced points by returning the start value and adding the stepwidth until the end is reached or surpassed.
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| 30 | /// </summary>
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| 31 | /// <param name="start">The smallest and first value of the sequence.</param>
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| 32 | /// <param name="end">The largest and last value of the sequence.</param>
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| 33 | /// <param name="stepWidth">The step size between subsequent values.</param>
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| 34 | /// <param name="includeEnd">Determines if the end should be included in the sequence regardless if the end is divisible by the stepwidth.</param>
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| 35 | /// <returns>A sequence of values from start to end (inclusive)</returns>
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| 36 | [Obsolete("It is recommended to use the decimal overload to achieve a higher numerical accuracy.")]
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| 37 | public static IEnumerable<double> GenerateSteps(double start, double end, double stepWidth, bool includeEnd = false) {
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| 38 | //mkommend: IEnumerable.Cast fails due to boxing and unboxing of the involved types
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| 39 | // http://referencesource.microsoft.com/#System.Core/System/Linq/Enumerable.cs#27bb217a6d5457ec
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| 40 | // http://blogs.msdn.com/b/ericlippert/archive/2009/03/19/representation-and-identity.aspx
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| 41 |
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| 42 | return GenerateSteps((decimal)start, (decimal)end, (decimal)stepWidth, includeEnd).Select<decimal, double>(x => (double)x);
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| 43 | }
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| 44 |
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| 45 | /// <summary>
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| 46 | /// Generates a sequence of evenly spaced points by returning the start value and adding the stepwidth until the end is reached or surpassed.
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| 47 | /// </summary>
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| 48 | /// <param name="start">The smallest and first value of the sequence.</param>
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| 49 | /// <param name="end">The largest and last value of the sequence.</param>
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| 50 | /// <param name="stepWidth">The step size between subsequent values.</param>
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| 51 | /// /// <param name="includeEnd">Determines if the end should be included in the sequence regardless if the end is divisible by the stepwidth.</param>
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| 52 | /// <returns>A sequence of values from start to end</returns>
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| 53 | public static IEnumerable<decimal> GenerateSteps(decimal start, decimal end, decimal stepWidth, bool includeEnd = false) {
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| 54 | if (stepWidth == 0)
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| 55 | throw new ArgumentException("The step width cannot be zero.");
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| 56 | if (start < end && stepWidth < 0)
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| 57 | throw new ArgumentException("The step width must be larger than zero for increasing sequences (start < end).");
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| 58 | if (start > end && stepWidth > 0)
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| 59 | throw new ArgumentException("The step width must be smaller than zero for decreasing sequences (start > end).");
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| 60 |
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| 61 | decimal x = start;
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| 62 | while (x <= end) {
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| 63 | yield return x;
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| 64 | x += stepWidth;
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| 65 | }
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| 66 | if (x - stepWidth < end && includeEnd) yield return end;
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| 67 | }
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| 68 | }
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| 69 | } |
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