Monte Carlo PI Visualizer

%Calculates for a given number of points an approximation of pi.

close all

clear

clc

num = input('How many points would you like to use?\n');

if (num < 3) || ((fix(num)-num) ~= 0 )

   error('Input must be a positive integer greater than 2')

end

type = input('Would you like to make a graph?[Y/N]\n','s');

% Variables

numcirpt = 0;

allpt = num;

%Using a for loop, x and y coord are created and their

% distance from the origin is calculated.

% If it is less than or equal to 1 it is a point that is in the area of a circle

% otherwise it is in the area of the square along with all of the generated points

%

%

rng("shuffle");

switch(type)

   case('Y')

       figure

       hold on

       for i = 1:num

       x = rand(1);

       y = rand(1); 

       dist = sqrt(x^2+y^2);

           if dist <= 1

           numcirpt = numcirpt + 1;

           plot(x,y,'.r');

           else

           plot(x,y,'.k');

           end

       end

       hold off

   case 'N'    

       for i = 1:num

       x = rand(1);

       y = rand(1);

       dist = sqrt(x^2+y^2);

       if dist <= 1

       numcirpt = numcirpt + 1;

       end

       end

end

%The ratio of

piapprox = 4 * numcirpt / allpt;

if piapprox == 0

   error('Make sure your inputs are correct!')

end

sprintf('The approx value of pi is %f',piapprox)

sprintf('The value of pi is %f',pi)