diff --git a/src/MathNet.Numerics.4.5.resharper b/src/MathNet.Numerics.4.5.resharper index d6c48cd3..73833a90 100644 --- a/src/MathNet.Numerics.4.5.resharper +++ b/src/MathNet.Numerics.4.5.resharper @@ -13,7 +13,7 @@ Wikipedia Cholesky Bluestein - +Chebyshev @@ -33,7 +33,7 @@ Bluestein false - 80 + 120 @@ -790,7 +790,9 @@ Bluestein CHOP_ALWAYS CHOP_IF_LONG - + + True + diff --git a/src/Numerics/Numerics.csproj b/src/Numerics/Numerics.csproj index d976fe73..77ecedee 100644 --- a/src/Numerics/Numerics.csproj +++ b/src/Numerics/Numerics.csproj @@ -96,6 +96,8 @@ True Resources.resx + + diff --git a/src/Numerics/Sampling/Sample.Chebyshev.cs b/src/Numerics/Sampling/Sample.Chebyshev.cs new file mode 100644 index 00000000..26ab1363 --- /dev/null +++ b/src/Numerics/Sampling/Sample.Chebyshev.cs @@ -0,0 +1,126 @@ +// +// Math.NET Numerics, part of the Math.NET Project +// http://mathnet.opensourcedotnet.info +// +// Copyright (c) 2009 Math.NET +// +// Permission is hereby granted, free of charge, to any person +// obtaining a copy of this software and associated documentation +// files (the "Software"), to deal in the Software without +// restriction, including without limitation the rights to use, +// copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the +// Software is furnished to do so, subject to the following +// conditions: +// +// The above copyright notice and this permission notice shall be +// included in all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES +// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT +// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, +// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING +// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR +// OTHER DEALINGS IN THE SOFTWARE. +// + +namespace MathNet.Numerics.Sampling +{ + using System; + + /// + /// Generic Function Sampling and Quantization Provider + /// + public static partial class Sample + { + /// + /// Samples a function at the roots of the Chebyshev polynomial of the first kind. + /// + /// The real-domain function to sample. + /// The real domain interval begin where to start sampling. + /// The real domain interval end where to stop sampling. + /// The number of samples to generate. + /// The value type of the function to sample. + /// Vector of the function sampled in [a,b] at (b+a)/2+(b-1)/2*cos(pi*(2i-1)/(2n)) + /// + /// + public static T[] ChebyshevNodesFirstKind( + Func function, + double intervalBegin, + double intervalEnd, + int sampleCount) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 1) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + // transform to map to [-1..1] interval + double transformSummand = 0.5 * (intervalBegin + intervalEnd); + double transformFactor = 0.5 * (intervalEnd - intervalBegin); + + // evaluate first kind chebyshev nodes + double angleFactor = Constants.Pi / (2 * sampleCount); + + var samples = new T[sampleCount]; + + for (int i = 0; i < samples.Length; i++) + { + samples[i] = function(transformSummand + transformFactor * Math.Cos(((2 * i) + 1) * angleFactor)); + } + + return samples; + } + + /// + /// Samples a function at the roots of the Chebyshev polynomial of the second kind. + /// + /// The real-domain function to sample. + /// The real domain interval begin where to start sampling. + /// The real domain interval end where to stop sampling. + /// The number of samples to generate. + /// The value type of the function to sample. + /// Vector of the function sampled in [a,b] at (b+a)/2+(b-1)/2*cos(pi*i/(n-1)) + /// + /// + public static T[] ChebyshevNodesSecondKind( + Func function, + double intervalBegin, + double intervalEnd, + int sampleCount) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 1) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + // transform to map to [-1..1] interval + double transformSummand = 0.5 * (intervalBegin + intervalEnd); + double transformFactor = 0.5 * (intervalEnd - intervalBegin); + + // evaluate second kind chebyshev nodes + double angleFactor = Constants.Pi / (sampleCount + 1); + + var samples = new T[sampleCount]; + + for (int i = 0; i < samples.Length; i++) + { + samples[i] = function(transformSummand + transformFactor * Math.Cos((i + 1) * angleFactor)); + } + + return samples; + } + } +} \ No newline at end of file diff --git a/src/Numerics/Sampling/Sample.Equidistant.cs b/src/Numerics/Sampling/Sample.Equidistant.cs new file mode 100644 index 00000000..58b30594 --- /dev/null +++ b/src/Numerics/Sampling/Sample.Equidistant.cs @@ -0,0 +1,368 @@ +// +// Math.NET Numerics, part of the Math.NET Project +// http://mathnet.opensourcedotnet.info +// +// Copyright (c) 2009 Math.NET +// +// Permission is hereby granted, free of charge, to any person +// obtaining a copy of this software and associated documentation +// files (the "Software"), to deal in the Software without +// restriction, including without limitation the rights to use, +// copy, modify, merge, publish, distribute, sublicense, and/or sell +// copies of the Software, and to permit persons to whom the +// Software is furnished to do so, subject to the following +// conditions: +// +// The above copyright notice and this permission notice shall be +// included in all copies or substantial portions of the Software. +// +// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, +// EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES +// OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND +// NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT +// HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, +// WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING +// FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR +// OTHER DEALINGS IN THE SOFTWARE. +// + +namespace MathNet.Numerics.Sampling +{ + using System; + using System.Collections.Generic; + + /// + /// Generic Function Sampling and Quantization Provider + /// + public static partial class Sample + { + /// + /// Samples a function equidistant within the provided interval. + /// + /// The real-domain function to sample. + /// The real domain interval begin where to start sampling. + /// The real domain interval end where to stop sampling. + /// The number of samples to generate. + /// The value type of the function to sample. + /// The generated sample vector. + /// + /// + public static T[] EquidistantInterval( + Func function, + double intervalBegin, + double intervalEnd, + int sampleCount) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 0) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + if (sampleCount == 0) + { + return new T[0]; + } + + if (sampleCount == 1) + { + return new T[] { function(0.5 * (intervalBegin + intervalEnd)) }; + } + + var samples = new T[sampleCount]; + var step = (intervalEnd - intervalBegin) / (sampleCount - 1); + var current = intervalBegin; + + for (int i = 0; i < samples.Length - 1; i++) + { + samples[i] = function(current); + current += step; + } + + samples[samples.Length - 1] = function(intervalEnd); + + return samples; + } + + /// + /// Samples a function equidistant within the provided interval. + /// + /// The real-domain function to sample. + /// The real domain interval begin where to start sampling. + /// The real domain interval end where to stop sampling. + /// The number of samples to generate. + /// The real domain points where the samples are taken at. + /// The value type of the function to sample. + /// The generated sample vector. + /// + /// + public static T[] EquidistantInterval( + Func function, + double intervalBegin, + double intervalEnd, + int sampleCount, + out double[] samplePoints) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 0) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + if (sampleCount == 0) + { + samplePoints = new double[0]; + return new T[0]; + } + + if (sampleCount == 1) + { + samplePoints = new[] { 0.5 * (intervalBegin + intervalEnd) }; + return new T[] { function(samplePoints[0]) }; + } + + var samples = new T[sampleCount]; + samplePoints = new double[sampleCount]; + var step = (intervalEnd - intervalBegin) / (sampleCount - 1); + var current = intervalBegin; + + for (int i = 0; i < samples.Length - 1; i++) + { + samplePoints[i] = current; + samples[i] = function(current); + current += step; + } + + samplePoints[samplePoints.Length - 1] = intervalEnd; + samples[samples.Length - 1] = function(intervalEnd); + + return samples; + } + + /// + /// Samples a periodic function equidistant within one period, but omits the last sample such that the sequence + /// can be concatenated together. + /// + /// The real-domain function to sample. + /// The real domain full period length. + /// The real domain offset where to start the sampling period. + /// The number of samples to generate. + /// The value type of the function to sample. + /// The generated sample vector. + /// + /// + public static T[] EquidistantPeriodic( + Func function, + double periodLength, + double periodOffset, + int sampleCount) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 1) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + var samples = new T[sampleCount]; + var step = periodLength / sampleCount; + var current = periodOffset; + + for (int i = 0; i < samples.Length; i++) + { + samples[i] = function(current); + current += step; + } + + return samples; + } + + /// + /// Samples a periodic function equidistant within one period, but omits the last sample such that the sequence + /// can be concatenated together. + /// + /// The real-domain function to sample. + /// The real domain full period length. + /// The real domain offset where to start the sampling period. + /// The number of samples to generate. + /// The real domain points where the samples are taken at. + /// The value type of the function to sample. + /// The generated sample vector. + /// + /// + public static T[] EquidistantPeriodic( + Func function, + double periodLength, + double periodOffset, + int sampleCount, + out double[] samplePoints) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 1) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + var samples = new T[sampleCount]; + samplePoints = new double[sampleCount]; + var step = periodLength / sampleCount; + var current = periodOffset; + + for (int i = 0; i < samples.Length; i++) + { + samplePoints[i] = current; + samples[i] = function(current); + current += step; + } + + return samples; + } + + /// + /// Samples a function equidistant starting from the provided location with a fixed step length. + /// + /// The real-domain function to sample. + /// The real domain location offset where to start sampling. + /// The real domain step length between the equidistant samples. + /// The number of samples to generate. + /// The value type of the function to sample. + /// The generated sample vector. + /// + /// + public static T[] EquidistantStartingAt( + Func function, + double start, + double step, + int sampleCount) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 0) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + var samples = new T[sampleCount]; + var current = start; + + for (int i = 0; i < samples.Length; i++) + { + samples[i] = function(current); + current += step; + } + + return samples; + } + + /// + /// Samples a function equidistant starting from the provided location with a fixed step length. + /// + /// The real-domain function to sample. + /// The real domain location offset where to start sampling. + /// The real domain step length between the equidistant samples. + /// The number of samples to generate. + /// The real domain points where the samples are taken at. + /// The value type of the function to sample. + /// The generated sample vector. + /// + /// + public static T[] EquidistantStartingAt( + Func function, + double start, + double step, + int sampleCount, + out double[] samplePoints) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + if (sampleCount < 0) + { + throw new ArgumentOutOfRangeException("sampleCount"); + } + + var samples = new T[sampleCount]; + samplePoints = new double[sampleCount]; + var current = start; + + for (int i = 0; i < samples.Length; i++) + { + samplePoints[i] = current; + samples[i] = function(current); + current += step; + } + + return samples; + } + + /// + /// Samples a function equidistant continuously starting from the provided location with a fixed step length. + /// + /// The real-domain function to sample. + /// The real domain location offset where to start sampling. + /// The real domain step length between the equidistant samples. + /// The value type of the function to sample. + /// The generated sample enumerator. + /// + public static IEnumerable EquidistantContinuous( + Func function, + double start, + double step) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + var current = start; + + while (true) + { + yield return function(current); + current += step; + } + } + + /// + /// Samples a function equidistant with the provided start and step length to an integer-domain function + /// + /// The real-domain function to sample. + /// The real domain location where to start sampling. + /// The real domain step length between the equidistant samples. + /// The value type of the function to sample. + /// The generated samples integer-domain function. + /// + public static Func EquidistantToFunction( + Func function, + double start, + double step) + { + if (ReferenceEquals(function, null)) + { + throw new ArgumentNullException("function"); + } + + return k => function(start + k * step); + } + } +} \ No newline at end of file