/// <summary> /// Fits data provided as xcolumn and ycolumn with a polynomial base. /// </summary> /// <param name="order">The order of the fit (1:linear, 2:quadratic, etc.)</param> /// <param name="xcolumn">The column of x-values.</param> /// <param name="ycolumn">The column of y-values.</param> /// <returns>The fit.</returns> public static LinearFitBySvd Fit(int order, Altaxo.Data.DataColumn xcolumn, Altaxo.Data.DataColumn ycolumn) { if (!(xcolumn is Altaxo.Data.INumericColumn)) { throw new ArgumentException("The x-column must be numeric", "xcolumn"); } if (!(ycolumn is Altaxo.Data.INumericColumn)) { throw new ArgumentException("The y-column must be numeric", "ycolumn"); } int firstIndex = 0; int count = Math.Min(xcolumn.Count, ycolumn.Count); double[] xarr = new double[count]; double[] yarr = new double[count]; double[] earr = new double[count]; var xcol = (Altaxo.Data.INumericColumn)xcolumn; var ycol = (Altaxo.Data.INumericColumn)ycolumn; int numberOfDataPoints = 0; int endIndex = firstIndex + count; for (int i = firstIndex; i < endIndex; i++) { double x = xcol[i]; double y = ycol[i]; if (double.IsNaN(x) || double.IsNaN(y)) { continue; } xarr[numberOfDataPoints] = x; yarr[numberOfDataPoints] = y; earr[numberOfDataPoints] = 1; numberOfDataPoints++; } return(LinearFitBySvd.FitPolymomialDestructive(order, xarr, yarr, earr, numberOfDataPoints)); }
public static string Fit(Altaxo.Gui.Graph.Gdi.Viewing.IGraphController ctrl, int order, double fitCurveXmin, double fitCurveXmax, bool showFormulaOnGraph) { string error; error = GetActivePlotPoints(ctrl, out var xarr, out var yarr); int numberOfDataPoints = xarr.Length; if (null != error) { return(error); } string[] plotNames = GetActivePlotName(ctrl); int numberOfParameter = order + 1; double[] parameter = new double[numberOfParameter]; var fit = LinearFitBySvd.FitPolymomialDestructive(order, xarr, yarr, null, numberOfDataPoints); // Output of results Current.Console.WriteLine(""); Current.Console.WriteLine("---- " + DateTime.Now.ToString() + " -----------------------"); Current.Console.WriteLine("Polynomial regression of order {0} of {1} over {2}", order, plotNames[1], plotNames[0]); Current.Console.WriteLine( "Name Value Error F-Value Prob>F"); for (int i = 0; i < fit.Parameter.Length; i++) { Current.Console.WriteLine("A{0,-3} {1,20} {2,20} {3,20} {4,20}", i, fit.Parameter[i], fit.StandardErrorOfParameter(i), fit.TofParameter(i), 1 - FDistribution.CDF(fit.TofParameter(i), numberOfParameter, numberOfDataPoints - 1) ); } Current.Console.WriteLine("R²: {0}, Adjusted R²: {1}", fit.RSquared, fit.AdjustedRSquared); Current.Console.WriteLine("Condition number: {0}, Loss of precision (digits): {1}", fit.ConditionNumber, Math.Log10(fit.ConditionNumber)); Current.Console.WriteLine("------------------------------------------------------------"); Current.Console.WriteLine("Source of Degrees of"); Current.Console.WriteLine("variation freedom Sum of Squares Mean Square F0 P value"); double regressionmeansquare = fit.RegressionCorrectedSumOfSquares / numberOfParameter; double residualmeansquare = fit.ResidualSumOfSquares / (numberOfDataPoints - numberOfParameter - 1); Current.Console.WriteLine("Regression {0,10} {1,20} {2,20} {3,20} {4,20}", numberOfParameter, fit.RegressionCorrectedSumOfSquares, fit.RegressionCorrectedSumOfSquares / numberOfParameter, regressionmeansquare / residualmeansquare, 1 - FDistribution.CDF(regressionmeansquare / residualmeansquare, numberOfParameter, numberOfDataPoints - 1) ); Current.Console.WriteLine("Residual {0,10} {1,20} {2,20}", numberOfDataPoints - 1 - numberOfParameter, fit.ResidualSumOfSquares, residualmeansquare ); Current.Console.WriteLine("Total {0,10} {1,20}", numberOfDataPoints - 1, fit.TotalCorrectedSumOfSquares ); Current.Console.WriteLine("------------------------------------------------------------"); // add the fit curve to the graph IScalarFunctionDD plotfunction = new PolynomialFunction(fit.Parameter); var fittedCurve = new XYFunctionPlotItem(new XYFunctionPlotData(plotfunction), new G2DPlotStyleCollection(LineScatterPlotStyleKind.Line, ctrl.Doc.GetPropertyContext())); var xylayer = ctrl.ActiveLayer as XYPlotLayer; if (null != xylayer) { xylayer.PlotItems.Add(fittedCurve); } return(null); }