# fig8_3

## PURPOSE

Local Regression and Likelihood, Figure 8.3.

## SYNOPSIS

This is a script file.

## DESCRIPTION

     Local Regression and Likelihood, Figure 8.3.

     Discrimination/Classification, iris data for different
     smooting paramters.

     Note that the iris.mat file contains the full iris dataset;
     only Versicolor and Virginica are used in this example.

     The `Species' variable contains species names. `Specn' has
     them numerically, Setosa=1, Versicolor=2, Virginica=3.

     Author: Catherine Loader

     Need: get contour plot correct.
     Need: distinguish colors in plot.

## CROSS-REFERENCE INFORMATION

This function calls:

- fitted Fitted values from a locfit object.
- lfplot Plot (for one or two dimensions) a locfit() fit.
- locfit Smoothing noisy data using Local Regression and Likelihood.

This function is called by:

- runbook

## SOURCE CODE

    0001 % Local Regression and Likelihood, Figure 8.3.
    0002 %
    0003 % Discrimination/Classification, iris data for different
    0004 % smooting paramters.
    0005 %
    0006 % Note that the iris.mat file contains the full iris dataset;
    0007 % only Versicolor and Virginica are used in this example.
    0008 %
    0009 % The `Species' variable contains species names. `Specn' has
    0010 % them numerically, Setosa=1, Versicolor=2, Virginica=3.
    0011 %
    0012 % Author: Catherine Loader
    0013 %
    0014 % Need: get contour plot correct.
    0015 % Need: distinguish colors in plot.
    0016
    0017 load iris;
    0018 a = (2:9)/10;
    0019 z = zeros(size(a));
    0020
    0021 u = find(Specn >= 2);
    0022 pw = PetalWid(u);
    0023 pl = PetalLen(u);
    0024 y = (Specn(u)==3);
    0025
    0026 for i = 1:length(a)
    0027   fit = locfit([pw pl],y,'deg',1,'alpha',a(i),'ev','cros','scale',0,'family','binomial');
    0028   fv = fitted(fit);
    0029   tb = tabulate(10*y+(fv>=0.5))
    0030   z(i) = sum(y == (fv<=0.5));
    0031 end;
    0032
    0033 [a; z]
    0034
    0035 fit = locfit([pw pl],y,'deg',1,'scale',0,'family','binomial');
    0036 figure('Name','fig8_3: iris classification');
    0037 lfplot(fit,'contour');
    0038