Contents

Plotlinear.m

From A First Course in Machine Learning, Chapter 1. Simon Rogers, 31/10/11 [simon.rogers@glasgow.ac.uk]

clear all;close all;

Define two points for the x-axis

x = [-5 5];

Define the different intercepts and gradients to plot

w0 = [0:1:20];
w1 = [0:0.4:8];

Plot all of the lines

figure(1);
hold off

for i = 1:length(w0)
    plot(x,w0(i)+w1(i).*x);
    hold all
    fprintf('\ny = %g + %g x',w0(i),w1(i));
end

y = 0 + 0 x
y = 1 + 0.4 x
y = 2 + 0.8 x
y = 3 + 1.2 x
y = 4 + 1.6 x
y = 5 + 2 x
y = 6 + 2.4 x
y = 7 + 2.8 x
y = 8 + 3.2 x
y = 9 + 3.6 x
y = 10 + 4 x
y = 11 + 4.4 x
y = 12 + 4.8 x
y = 13 + 5.2 x
y = 14 + 5.6 x
y = 15 + 6 x
y = 16 + 6.4 x
y = 17 + 6.8 x
y = 18 + 7.2 x
y = 19 + 7.6 x
y = 20 + 8 x

Request user input

close all;
figure(1);hold off
fprintf('\nKeeps plotting lines on the current plot until you quit (ctrl-c)\n');
while 1
    intercept = str2num(input('Enter intercept:','s'));
    gradient = str2num(input('Enter gradient:','s'));
    plot(x,intercept + gradient.*x);hold all
    fprintf('\n y = %g + %g x\n\n',intercept,gradient);
end

Keeps plotting lines on the current plot until you quit (ctrl-c)

Error using ==> input
Cannot call INPUT from EVALC.

Error in ==> plotlinear at 29
    intercept = str2num(input('Enter intercept:','s'));

Published with MATLAB® 7.12