Output argument "min_dist" (and maybe others) not assigned during call to

this is my main code I am trying to calculate the minimum distance between any number of points. In the case of a line there a re multiple, so standard deviation is used to find the ideal point.

clc;clear all;x=1;
data_points = input('How m

    if true
      % code
    endany data points would you like to enter: ');
  integer_test =~ mod(data_points,1);
  while x == 1;
   if data_points < 0 || integer_test == 0;
      data_points = input('Invalid! Enter a positive integer: ');
    integer_test =~ mod(data_points,1);
   else data_points > 0 && integer_test == 1;x=2;
      x_range = input('Enter the randge and spacing of x [xmin:dx:xmax]:');
      y_range = input('Enter the randge and spacing of y [ymin:dy:ymax]:');
      points = 1;xmin=min(x_range);xmax=max(x_range);ymin=min(y_range);ymax=max(y_range);
    prompt = ['Enter point ' num2str(points) ' [x,y] (' num2str(xmin) '<=x<=' num2str(xmax) ',' num2str(ymin) '<=y<=' num2str(ymax) '):'];
        diet(points,:) = input(prompt);
      while points <= data_points
            if diet(points,2)>ymax || diet(points,2)<ymin || diet(points,1)<xmin || diet(points,1)>xmax
            prompt_2 = ['Please enter point ' num2str(points) ' again [x,y]: '];
              fprintf('The entered point is not within the range of %g<=x<=%g and/or %g<=y<=%g\n',xmin,xmax,ymin,ymax);7
              diet(points,:) = input(prompt_2); 
           else diet(points,2)<ymax & diet(points,2)>ymin & diet(points,1)>xmin & diet(points,1)<xmax;
                   sharpie(points,:) = [points,diet(points,1),diet(points,2)];
              points = points +1;
              if points <= data_points
              prompt = ['Enter point ' num2str(points) ' [x,y] ...
  (' num2str(xmin) '<=x<=' num2str(xmax) ',' num2str(ymin) '<=y<=' num2str(ymax) '):'];
             diet(points,:) = input(prompt);
              end
           end
       end

       [min_dist,min_point,final_array] = ... final_function(x_range,y_range,sharpie);

      complete_array = [sharpie(:,1:3) (final_array)'];

      fprintf('The point that minimizes distnace is(a,b) = (%g,%g)\n\n',min_point(1),min_point(2))
  fprintf('The total minimum distance is %g\n\n',min_dist)
      disp(complete_array)

      x=complete_array(:,2);x_2 = min_point(1);z=complete_array(:,1);
  y=complete_array(:,3);y_2 = min_point(2);
  plot(x,y,'bo','MarkerFaceColor','b','MarkerSize',10)
  hold on;
  plot(x_2,y_2,'ro','MarkerFaceColor','r','MarkerSize',10)
  text(x-.09,y,num2cell(z),'Color','w'); 
  xlabel('x-coordinate','FontSize',14)
  ylabel('y-coordinate','FontSize',14)
  title('Final Project by Nate Steele','FontSize',14)
  h = legend('Entered Points','Minimum Point');
  set(h,'FontSize',14,'Location','best')

   end
  end

when i run this function I get the error in the title

function [min_dist,min_point,final_array] = final_function(x_range,y_range,sharpie)

[sharpie_size,k] = size(sharpie);

distance = zeros(1,sharpie_size);
final_array = sum(distance) + 1000000;
for i = x_range 
    for j = y_range
            for times = 1:sharpie_size

              distance(times)  = sqrt((i-sharpie(times,2))^2+(j-sharpie(times,3))^2);     

              end

                 if std2(distance) < std2(final_array)
                      min_point = [i,j];
                                   final_array = distance;  
                   min_dist = sum(final_array);
                 end

           distance = zeros(1,sharpie_size);   
      end

end

this is the information i am supposed to calculate

How many data points would you like to enter: 4
Enter the randge and spacing of x [xmin:dx:xmax]:[0:.1:10]
Enter the randge and spacing of y [ymin:dy:ymax]:[0:.1:10]
Enter point 1 [x,y] (0<=x<=10,0<=y<=10):[1.2,2.8]
Enter point 2 [x,y] (0<=x<=10,0<=y<=10):[3,7]
Enter point 3 [x,y] (0<=x<=10,0<=y<=10):[5.67,1.02]
Enter point 4 [x,y] (0<=x<=10,0<=y<=10):[7.8,8.2]

Answer 1

[Wayne King]

Without running your code, I see that you have min_dist assigned inside an if statement

if std2(distance) < std2(final_array)
                      min_point = [i,j];
                                   final_array = distance;  
                   min_dist = sum(final_array);
 end

What if std2(distance) > std2(final_array) ?

Then min_dist is not assigned any value.

Is that really want you want to do? It's not good practice to have a function outputting an argument which is possibly not even created in the function.

Can you at least assign it some fallback value in case that if statement evaluates to false?

[nathaniel]

thank you! i figured out that problem, but i cant get the code to return the right answer. it is calculating improperly somewhere

[Image Analyst]

This will help with that problem immensely: http://blogs.mathworks.com/videos/2012/07/03/debugging-in-matlab/