MATLAB Programming/Plot

Introduction

The plot command plots 2D data linearly to the current axis on the current figure.

Usage

Here's how a plot can be created.

  >> h = figure;                                   % Create new figure and save the handle to h
  >> x = [0:0.001:10];                         % Create x vector
  >> y = sin(x);
  >> plot(x, y)                                      % Plot
  >> title('Sine wave from 0 to 10')        % Set the title of the current axis
  >> ylabel('sin(x)')                              % Set the label for the y-axis
  >> xlabel('x') %set the label for the x-axis
% xlabel('alpha') - - > alpha
% xalbel('\alpha') - -> symbolic alpha
  >> grid on                                         % Turn on the grid

Graphs can also be created and saved using the command line interface. For example, the following code will create a graph comparing the speedup of two algorithms. The graph created is shown below.

  >> x = [1 2 4 8];
  >> y = [1 2 1.95 3.79];
  >> z = [1 1.73 2.02 3.84]; 
  >> h = plot(x,y,'--');
  >> hold on; % Plot next graph on same figure
  >> plot(x,z);
  >> hold off;
  >> xlabel('Number of processors');
  >> ylabel('Speedup');
  >> saveas(h,'graph.eps',eps);

External Links

MATLAB category on ControlTheoryPro.com

Matlab tutorial in French