Error in Code for Lighting: "Index in position 1 is invalid. Array indices must be positive integers or logical values."

I am using this old code produced for EWB to calculate the lighting needs inside of a classroom. I am not proficient enough in Matlab to figure out what is going wrong. It specifically doesn't like the barlight variable, I have tried different things but it does not like modificaitons. Please let me know your suggestions.

%MATLAB Code for Light Intensity Calculation 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% CLEANUP %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
clear 
%clc 
close all 
set(0, 'DefaultAxesFontName', 'Times New Roman' ) 
set(0, 'DefaultAxesFontSize', 11 ) 
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% INPUT %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
% Building dimensions 
h= 9;                       % [ft] Distance floor to ceiling 
L=22.87;                    % [ft] Length associated with x dimension 
W=15.81;                    % [ft] Length associated with y dimension 
s=2.5;                      % [ft] Height of desk 
res=0.025;                  % Resolution of sample grid  
% Lighting Information (Type 1 = LF, Type 2 = LED) 
length_l=[1.7 1.0];         % Length of bar light 
brightness=[830 960];       % lumens/light 
EOL=[0.8 .85];              % Light derating factor 
light_used= [.487 .649];    % Percent of light reaching desired plane 
%Reference (LF):  http://www.selux.us/fileadmin/us/interior/Spec_Sheet/M125/M125_F_SS-1.pdf 
%Reference (LED): http://www.gelighting.com/LightingWeb/na/images/IND029-GE-Lumination-LED-Lighting-Fixtures-BL-Recessed-Spec-Sheet.pdf 
num_lights = [7 6]; 
num_rows   = [2 2]; 
num_cols   = ceil( num_lights ./ num_rows ); 
last_col_rows = mod( num_lights, num_rows ); 
for type=1:2 
    if( last_col_rows(type) == 0 ) 
        last_col_rows(type) = num_rows(type); 
    end 
end 


% Perform analysis for both LED's and Linear Fluorescents 
for type=1:2 
    type_name = ''; 
    if( type == 1 ) 
        type_name = 'Linear Fluorescent'; 
    elseif( type == 2 ) 
        type_name = 'LED'; 
    end  
    disp( ' ' ); 
    disp( strcat( type_name, ' Analysis' ) ); 
    disp( '-------------------------------' ); 
    %%%%%%%%%%%%%%%%%%%%%%%%%%%% Light placement %%%%%%%%%%%%%%%%%%%%%%%%%% 
    col_distance = L /num_cols(type); 
    col_distance_adjust = col_distance/2 * (1 - last_col_rows(type)/num_rows(type) ); 
    row_distance = ( W - (num_rows(type) * length_l(type) ) )/num_rows(type); 
    row_distance_last_col = ( W - (last_col_rows(type) * length_l(type) ) )/last_col_rows(type); 
    x_coord = col_distance/2:col_distance:(L-col_distance/2); 
    x_coord = x_coord + col_distance_adjust; 
    y_coord = row_distance/2:row_distance+length_l(type):(W-row_distance/2); 
    y_coord_last_col = row_distance_last_col/2:row_distance_last_col+length_l(type):(W- row_distance_last_col/2); 
    
    %%%%%%%%%%%%%%%%%%%%%%%%%%%% Calculations %%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
    z=h-s; %[ft] vertical distance from lights to desk 
    % Formatting vectors 
    X=0:res:L;        % Vector of x steps 
    Y=0:res:W;        % Vector of y steps 
    LY=length(Y);       % Y vector length  
    LX=length(X);       % X vector length 
    Z=ones(LX,LY)*z;    % Vector of z steps 
    % Adjust brightness by derating factor and coefficient of utilization 
    bright=EOL(type)*brightness(type)*light_used(type);  
    % Generate the light maps (sum them as you go) 
    lightTot= 0;
    for c=1:num_cols(type)-1 
        for r=1:num_rows(type) 
            lightTot = lightTot + barlight(X,Y,Z,x_coord(c),y_coord(r),x_coord(c),y_coord(r) + length_l,res,bright); 
        end 
    end 
    % Last column separately to accomodate different spacing 
    for r=1:last_col_rows(type) 
        lightTot = lightTot + barlight( X,Y,Z,x_coord(num_cols(type)),y_coord_last_col(r), x_coord(num_cols(type)),y_coord_last_col(r) + length_l, res,bright);
    end 
    % Output lighting statistics 
    fprintf( 'Maximum Light Intensity:  %.2f\n',   max(  lightTot(:) ) ) ; 
    fprintf( 'Minimum Light Intensity:  %.2f\n',   min(  lightTot(:) ) ) ; 
    fprintf( 'Average Light Intensity:  %.2f\n',   mean( lightTot(:) ) ) ; 
    fprintf( 'Light Intensity Variance: %.2f\n\n', var(  lightTot(:) ) ) ; 
    
    totalmax = max(  max (lightTot) ); 
    
    
    %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% Plot %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 
    figure('Position', [100, 100, 1050, 750]); 
    mesh(X,Y,lightTot) %plot light intensity 
    axis( [0 L 0 W 0 totalmax] ) 
    view(2);   % Uncomment to get 2D overhead views 
    xlabel('Room Width (ft)', 'FontSize', 12) 
    ylabel('Room Length (ft)', 'FontSize', 12) 
    zlabel('Light Intensity (fc)', 'FontSize', 12) 
    title( sprintf( 'Light Intensity on Work Plane (%s) - Minimum = %.2f fc', type_name,  min(  lightTot(:) ) ), 'FontSize',13 ); 
    handle=colorbar; 
    xlabel(handle, 'Light Intensity (fc)', 'FontSize', 12); 
    
    %%%%Draw and label light placement%%%% 
    for c=1:num_cols(type)-1 
        for r=1:num_rows(type) 
            line([x_coord(c) x_coord(c)], [y_coord(r) y_coord(r) + length_l(type)],[totalmax totalmax],'LineWidth',3) ;
            text( x_coord(c),y_coord(r),totalmax, sprintf( 'Light %d-%d', r, c ) ); 
        end 
    end 
    
    % Last column separately to accomodate different spacing 
    for r=1:last_col_rows(type) 
        line([x_coord(num_cols(type)) x_coord(num_cols(type))],[y_coord_last_col(r) y_coord_last_col(r) + length_l(type)],[totalmax totalmax],'LineWidth',3);
        text( x_coord(num_cols(type)),y_coord_last_col(r),totalmax, sprintf( 'Light %d-%d', r,  num_cols(type))); 
    end 
end 

Linear Fluorescent Analysis

-------------------------------

Unrecognized function or variable 'barlight'.

disp( ' ' ); 

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% End %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%% 

Answer 1

[Image Analyst]

See the FAQ for a thorough discussion:

Subscript indices must either be real positive integers or logicals

You do this:

line([x_coord(c) x_coord(c)], [y_coord(r) y_coord(r) + length_l(type)],[totalmax totalmax],'LineWidth',3) ;

so x_coord needs to be an array. However you never assign elements of it. It's just a simple scalar like here in your for loop:

x_coord = col_distance/2:col_distance:(L-col_distance/2); 

so try giving it an index:

x_coord(type) = col_distance/2:col_distance:(L-col_distance/2); 

but don't use type as the name of an iterator since it's the name of a built in function type. Call it something else like k, but not "type", "i", or "j".