% Useful MATLAB commands

% Comments
% Anything behind a percent symbol is commented out

% Help on functions
% help function_name
help stepfun

% MATLAB primarily uses vectors and matrices to store data values
A = [1 2 3;
    4 5 6];
% Creates a 2x3 matrix
% Semicolon in the [] is used for creating a new row

% Access individual elements
% variable_name(row_value,column_value)
A(2,3)
% Returns the value 6
% This method can also be used to write to a specific element

% Access individual column or row
% Use a colon (:) in place of a row or column
A(:,1)
% Returns only the first column

% Creating a large, evenly spaced vector
% vector_name = low_value:increment_size:high_value;
tt = 0:0.1:10;

% Preventing MATLAB from echoing back all values
% Put a semicolon at the end of the line

% Size of a variable
% size(variable_name)
size(A)
% Returns the number of rows and columns

% Transpose a matrix
% matrix_name'
A'

% Point-by-point multiplication and division
% MATLAB defaults to matrix multiplication with *
% To perform point-by-point multiplication of two vectors, use .*
tt_squared = tt.*tt
% This also works with division (/) and exponentiation (^)

% Determining what variables are present
who           % lists all variables
whos          % lists all variables and their sizes

% To create a new figure
figure;
% Or, to create a specific figure number
figure(10);
% MATLAB will always plot to the previously selected figure

% Plotting
% plot(independant_variable,dependant_variable);
plot(tt,yy);
% You can change the color of the line with the optional argument
plot(tt,yy,'r')
% Type "help plot" for more options

% Stem plots
% Useful for plotting discrete-time signals
% stem(independant_variable,dependant_variable);
stem(tt,yy);

% Labeling your plots
% You must use text strings offset by ' marks
xlabel('Time (s)')
ylabel('Output')
title('The Example Signal')

% Multiple graphs in the same figure
% subplot(rows_of_plots,columns_of_plots,selected_plot)
subplot(2,1,1);
% Creates two plots (one above the other) and selects the top 
%      one for plotting

% Other useful plotting commands
% Create a legend for your plot
legend('Signal 1', 'Signal 2')
% Change the axes ranges
% axis([low_x high_x low_y high_y])
axis([-10 10 0 5]);
% Toggle the grid on or off
grid
% Hold the plot to allow another signal to be plotted
% on the same plot
hold on;

% Printing/saving plots
% Plots can be printed directly from the figure window
% Plots can also be saved
%      .fig files are the default from the pull-down menu
%           .fig files can only be reopened in MATLAB
%      metafile for use in Word documents and PowerPoint slides
%           copies the figure to the clipboard
print -dmeta
%      .eps files for use in LaTeX files
%           stores the image in a .eps file (Encapsulated PostScript)
%           called file_name.eps
print -dmeta file_name

% Saving your work
% save file_name variable_1 variable_2 ...
save ee327_example_1 A tt

% Creating .m files
% Script files and user-defined functions can be written in .m files
% To open a new .m file, click the "New File" button or type
edit
% Alternatively, you can open an existing .m file by typing
edit file_name

% Script files (.m files) can contain any code written at the MATLAB prompt
% This is useful for editing your work and staying organized
% This is also useful for having all the code written neatly for 
%      turning in your homework
% You can run a script file by typing its name at the command prompt
% You can also run the script by pressing F5 in the editor window

% Functions
% You can create your own functions by opening a new file and writing
%      your code.  The first line of the function must be
function [output_1,output_2] = my_function(input_1,input_2)
% Any comments directly following this line will be displayed to the 
%      screen if you type "help my_function"
% Then, write all your lines of code
% Make sure you write to the output variables