This is a test function called all_curves, which is a basic tutorial to plotting multiple curves on a single plot in MATLAB. This function plots lines based upon a given interval of temperatures and then analyzes them using the contained MATLAB function black_bodyf to analyze them using Planck's energy equation for black body emitter sources.

all_curves.m

% MATLAB
function all_curves(floor_temp, ceil_temp)

% Interactive example and tutotial for plotting multiple lines on a Matlab
% figure using black_body representative temperatures.
% Function takes in two values, a low (floor) temperature and a high (ceil)
% temperature and plots lines incremented between them. The function then
% plots each plotted_line based on each increment and then scales automatically to
% fit the values.

% WARNING: This function used the Matlab dependancy function black_bodyf. (Contained below)

    % Create a new figure for the lines to be plotted on.
    figure;

    %Set the size of the figure, as well as the position of the figure.
    set( gcf, 'Position', [10 10 1024 768] );

    % Preparation before the start of the loop:
    % Assign the style of the plotted_line as well as the colors that are
    % avalailable for use in the plot once the 'for loop' is triggered.
    % Also create an index variable, idx to increment from while the loop
    % runs.

    lineStyles  = '-:';
    colors      = 'rgbkcmy';
    idx         = 0;

    % Initiate the for loop, plot a value for every temperature between
    % 2000 and 10000 using a 2000 degree value increment.
    for temp=[floor_temp:2000:ceil_temp]

        % Assign a temporary variable based on the plot particulars and the
        % index variable, idx
        temporary_variable     = mod( idx, length(lineStyles) );
        plotted_line           = lineStyles( temporary_variable + 1 );

        temporary_variable     = mod( idx, length(colors) );
        clr                    = colors( temporary_variable + 1 );

        % Set the response equal to the value generated by the Matlab
        % function black_bodyf, a scientific calculator for Planckian
        % radiation scenarios.
        response               = black_bodyf( temp );

        % Plot the responses and define their line styles.
        plot( response(1,:), response(2,:), [clr plotted_line], 'LineWidth', 2 );
        hold on;

        % Increment the temporary variable for the next iteration through
        % the loop.
        idx                    = idx + 1;

        % Label the plot.
        label                  = sprintf('T = %6d', temp);
        allLabels{idx}         = label;

    end

    % Put a legend on the plot:
    legend( allLabels );

end

black_bodyf.m

function response = black_bodyf( temp )

% PURPOSE
%    Generates a standard curve for a input temperature based on a
%    standard Blackbody emitter.
% Jordan Westhoff, RIT 2015

wl	= [100:10:4000];

    idx = 1;

    % This is an example of the "set and correct" pattern.
    % The default values are set to something that indicates
    % 'wrong', and then they are corrected in the loop.

    response = zeros(2,length(wl));

    for wavelength = wl

        value           = planck_value(temp,wavelength);

        response(1,idx) = wavelength;
        response(2,idx) = value;


        idx             = idx + 1;
    end

end