Imports System Imports System.Globalization Imports System.Threading Imports System.Text Imports CenterSpace.NMath.Core Namespace CenterSpace.NMath.Examples.VisualBasic A .NET example in Visual Basic showing how to use the Discrete Wavelet Transform (DWT) classes. Module DWTExample Sub Main() This section shows to use various configuration settings. All of these settings can also be set via configuration file or by environment variable. More on this at: http://www.centerspace.net/blog/nmath/nmath-configuration/ For NMath to continue to work after your evaluation period, you must set your license key. You will receive a license key after purchase. More here: http://www.centerspace.net/blog/nmath/setting-the-nmath-license-key/ NMathConfiguration.LicenseKey = "<key>" This will start a log file that you can use to ensure that your configuration is correct. This can be especially useful for deployment. Please turn this off when you are convinced everything is working. If you arent sure, please send the resulting log file to support@centerspace.net. Please note that this directory can be relative or absolute. NMathConfiguration.LogLocation = "<dir>" NMath loads native, optimized libraries at runtime. There is a one-time cost to doing so. To take control of when this happens, use Init(). If your program calls Init() successfully, then your configuration is definitely correct. NMathConfiguration.Init() Console.WriteLine() DWT of a signal using the Harr wavelet. Do a simple DWT on a signal Dim Data As New DoubleVector(12, New RandGenNormal(0.0, 2.0)) Choose wavelet Dim WaveletInstance As New DoubleWavelet(Wavelet.Wavelets.Harr) Build DWT object Dim DWT As New DoubleDWT(WaveletInstance) Decompose signal with DWT Dim Approx() As Double Dim Details() As Double DWT.DWT(Data.DataBlock.Data, Approx, Details) Rebuild the signal Dim Signal() As Double = DWT.IDWT(Approx, Details) Print results Console.WriteLine() Console.WriteLine("A DWT signal decomposition and reconstruction example using the Harr wavelet.") Console.WriteLine(String.Format("Original Signal: {0}", Data.ToString("#.##"))) Console.WriteLine(String.Format("DWT Approximation: {0}", New DoubleVector(Approx).ToString("#.##"))) Console.WriteLine(String.Format("DWT Details: {0}", New DoubleVector(Details).ToString("#.##"))) Console.WriteLine(String.Format("IDWT Reconstructed signal: {0}", New DoubleVector(Signal).ToString("#.##"))) DWT using a Daubeachies wavelet, then thresholding, and finally reconstucting the signal. An example to filter a signal using the DWT. Build random signal data Data = New DoubleVector(26, New RandGenNormal(1.0, 1.0)) Choose wavelet WaveletInstance = New DoubleWavelet(Wavelet.Wavelets.D2) Build DWT object DWT = New DoubleDWT(Data.DataBlock.Data, WaveletInstance) Decompose signal with DWT to level 5 DWT.Decompose(3) Find Universal threshold Dim LambdaU As Double = DWT.ComputeThreshold(DoubleDWT.ThresholdMethod.Universal, 1) Threshold all detail levels with lambdaU DWT.ThresholdAllLevels(DoubleDWT.ThresholdPolicy.Soft, New Double() {LambdaU, LambdaU, LambdaU, LambdaU, LambdaU}) Rebuild signal to level 2 Dim ReconstructedData2() As Double = DWT.Reconstruct(2) Rebuild the signal to level 1 - the original (filtered) signal. Dim ReconstructedData1() As Double = DWT.Reconstruct() Print results Console.WriteLine() Console.WriteLine("A DWT signal thresholding and reconstruction example using a Daubeachies wavelet.") Console.WriteLine(String.Format("Original Signal: ")) Console.WriteLine(" {0}", Data.ToString("#.##")) Console.WriteLine() Console.WriteLine(String.Format("IDWT Reconstructed signal: ")) Console.WriteLine(" {0}", New DoubleVector(ReconstructedData1).ToString("#.##")) Console.WriteLine() Console.WriteLine("Finished. Press Enter Key.") Console.Read() End Sub End Module End Namespace← All NMath Code Examples