Sorry, you're right - this is a new example in Measurement Studio 7.1. I would post the example, but it uses new controls and features from Measurement Studio 7.1, so you wouldn't be able to build or run it. If you just want to see some example code that uses NonLinearFit and the ModelFunctionCallback, though, here is the relevant code from the example:
Private Sub GenerateDataToFit(ByVal numSamples As Integer, ByVal noiseAmplitude As Double, ByRef xData As Double(), ByRef yData As Double())
ReDim xData(numSamples - 1)
ReDim yData(numSamples - 1)
Dim noise As WhiteNoiseSignal = New WhiteNoiseSignal(noiseAmplitude, 0)
Dim noiseData As Double() = noise.Generate(numSamples, numSamples)
For x As Integer = 0 To xData.Length - 1
xData(x) = x
yData(x) = System.Math.Exp(-0.1 * x) + 2.0 + noiseData(x)
Next
End Sub
Private Sub OnCalculate(ByVal sender As Object, ByVal e As EventArgs) Handles calculateButton.Click
Dim numSamples As Integer = numberOfSamples.Value
Dim noiseAmplitude As Double = noiseLevel.Value
Dim xData As Double()
Dim yData As Double()
Dim coefficients As Double() = {2, 0, 4}
GenerateDataToFit(numSamples, noiseAmplitude, xData, yData)
scatteredDataPlot.PlotY(yData)
Dim mse As Double
Dim callback As ModelFunctionCallback = New ModelFunctionCallback(AddressOf ModelFunction)
Try
Dim fittedData As Double() = CurveFit.NonLinearFit(xData, yData, callback, coefficients, mse)
fitDataPlot.PlotY(fittedData)
Catch exp As Exception
MessageBox.Show(exp.Message)
End Try
End Sub
Private Function ModelFunction(ByVal x As Double, ByVal a As Double()) As Double
Return (a(0) * System.Math.Exp(a(1) * x)) + a(2)
End Function
- Elton
