From 7f5b414bbee7ce2fb1d635d255a88ca58689330d Mon Sep 17 00:00:00 2001
From: Christoph Ruegg <git@cdrnet.ch>
Date: Fri, 7 Oct 2016 13:39:27 +0200
Subject: [PATCH] FFT: fft provider mvp interface

---
 src/Numerics/Numerics.csproj                  |  2 +
 .../IFourierTransformProvider.cs              | 45 +++++++++++++++++++
 .../ManagedFourierTransformProvider.cs        | 34 ++++++++++++++
 3 files changed, 81 insertions(+)
 create mode 100644 src/Numerics/Providers/FourierTransform/IFourierTransformProvider.cs
 create mode 100644 src/Numerics/Providers/FourierTransform/ManagedFourierTransformProvider.cs

diff --git a/src/Numerics/Numerics.csproj b/src/Numerics/Numerics.csproj
index 0063697a..d224559c 100644
--- a/src/Numerics/Numerics.csproj
+++ b/src/Numerics/Numerics.csproj
@@ -172,6 +172,8 @@
       <DesignTime>True</DesignTime>
       <DependentUpon>Resources.resx</DependentUpon>
     </Compile>
+    <Compile Include="Providers\FourierTransform\IFourierTransformProvider.cs" />
+    <Compile Include="Providers\FourierTransform\ManagedFourierTransformProvider.cs" />
     <Compile Include="Providers\LinearAlgebra\Acml\AcmlLinearAlgebraProvider.Complex.cs" />
     <Compile Include="Providers\LinearAlgebra\Acml\AcmlLinearAlgebraProvider.Complex32.cs" />
     <Compile Include="Providers\LinearAlgebra\Acml\AcmlLinearAlgebraProvider.Double.cs" />
diff --git a/src/Numerics/Providers/FourierTransform/IFourierTransformProvider.cs b/src/Numerics/Providers/FourierTransform/IFourierTransformProvider.cs
new file mode 100644
index 00000000..7c6e5c77
--- /dev/null
+++ b/src/Numerics/Providers/FourierTransform/IFourierTransformProvider.cs
@@ -0,0 +1,45 @@
+// <copyright file="ILinearAlgebraProvider.cs" company="Math.NET">
+// Math.NET Numerics, part of the Math.NET Project
+// http://numerics.mathdotnet.com
+// http://github.com/mathnet/mathnet-numerics
+//
+// Copyright (c) 2009-2016 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.
+// </copyright>
+
+namespace MathNet.Numerics.Providers.FourierTransform
+{
+
+#if !NOSYSNUMERICS
+    using Complex = System.Numerics.Complex;
+#endif
+
+    public interface IFourierTransformProvider
+    {
+        void ForwardInplace(Complex[] complex);
+        void BackwardInplace(Complex[] complex);
+
+        Complex[] Forward(Complex[] complexTimeSpace);
+        Complex[] Backward(Complex[] complexFrequenceSpace);
+    }
+}
diff --git a/src/Numerics/Providers/FourierTransform/ManagedFourierTransformProvider.cs b/src/Numerics/Providers/FourierTransform/ManagedFourierTransformProvider.cs
new file mode 100644
index 00000000..f4afed72
--- /dev/null
+++ b/src/Numerics/Providers/FourierTransform/ManagedFourierTransformProvider.cs
@@ -0,0 +1,34 @@
+using System.Numerics;
+using MathNet.Numerics.IntegralTransforms;
+
+namespace MathNet.Numerics.Providers.FourierTransform
+{
+    public class ManagedFourierTransformProvider : IFourierTransformProvider
+    {
+        public void ForwardInplace(Complex[] complex)
+        {
+            Fourier.BluesteinForward(complex, FourierOptions.Default);
+        }
+
+        public void BackwardInplace(Complex[] complex)
+        {
+            Fourier.BluesteinInverse(complex, FourierOptions.Default);
+        }
+
+        public Complex[] Forward(Complex[] complexTimeSpace)
+        {
+            Complex[] work = new Complex[complexTimeSpace.Length];
+            complexTimeSpace.Copy(work);
+            ForwardInplace(work);
+            return work;
+        }
+
+        public Complex[] Backward(Complex[] complexFrequenceSpace)
+        {
+            Complex[] work = new Complex[complexFrequenceSpace.Length];
+            complexFrequenceSpace.Copy(work);
+            BackwardInplace(work);
+            return work;
+        }
+    }
+}