Class FitExponential


public class FitExponential extends NLFittedFunction
FitExponential -fits an array of points to an exponential of the type y = a0 + a1*exp(a2*x).
Version:
0.9
Author:
William Gandler
See Also:
  • Constructor Details

    • FitExponential

      public FitExponential()
      FitExponential - test constructor, builds and test function.
    • FitExponential

      public FitExponential(int nPoints, double[] xData, double[] yData)
      FitExponential.
      Parameters:
      nPoints - number of points in the function
      xData - DOCUMENT ME!
      yData - DOCUMENT ME!
    • FitExponential

      public FitExponential(int nPoints, float[] xData, float[] yData)
      Constructs new fit exponential.
      Parameters:
      nPoints - Number of points in the function
      xData - DOCUMENT ME!
      yData - DOCUMENT ME!
  • Method Details

    • driver

      public void driver()
      Starts the analysis. For some reason a guess with the wrong sign for a2 will not converge. Therefore, try both sign and take the one with the lowest chi-squared value.
      Overrides:
      driver in class NLConstrainedEngine
    • displayResults

      public void displayResults()
      Display results of displaying exponential fitting parameters.
      Specified by:
      displayResults in class NLFittedFunction
    • fitToFunction

      public void fitToFunction(double[] a, double[] residuals, double[][] covarMat)
      Fit to function - a0 + a1*exp(a2*x).
      Specified by:
      fitToFunction in class NLConstrainedEngine
      Parameters:
      a - The best guess parameter values.
      residuals - ymodel - yData.
      covarMat - The derivative values of y with respect to fitting parameters.
    • testData

      private void testData()
      Test data to test fitting of exponential.
    • calculateFittedY

      protected void calculateFittedY()
      Description copied from class: NLFittedFunction
      Calculates yDataFitted
      Specified by:
      calculateFittedY in class NLFittedFunction
    • generateResiduals

      protected Jama.Matrix generateResiduals()
      Description copied from class: NLFittedFunction
      Calculates the residuals for a given function, not implemented since some functions might prefer to only use a subset of data points, or not use yDataFitted if working during an iteration
      Specified by:
      generateResiduals in class NLFittedFunction
      Returns:
    • calculateChiSq

      protected void calculateChiSq()
      Description copied from class: NLFittedFunction
      Calculates chi squared
      Specified by:
      calculateChiSq in class NLFittedFunction