Help on a problem

I have this problem and I'm wondering if anyone can help me to figure it out. It goes as follows: write a program to iteratively generate points in two-dimensional space using the following rules:

    (x_{n+1},y_{n+1}) = 

/ (0.5,0.27*y_n),                                                  with 2% probability;
|                
| (-0.139*x_n + 0.263*y_n + 0.57, 0.246*x_n + 0.224*y_n - 0.036),  with 15% probability;
<
| (0.17*x_n - 0.215*y_n + 0.408, 0.222*x_n + 0.176*y_n + 0.0893),  with 13% probability;
|
\ (0.781*x_n + 0.034*y_n + 0.1075, -0.032*x_n + 0.739*y_n + 0.27), with 70% probability.

Start from an initial point (x_1,y_1)=(0.5,0.0). Carry out the iteration at least 30,000 times

Answer 1

[Walter Roberson]

for iter = 1: 30000
  r = rand() ;
  if r < 0.02
   .... 
  elseif r < 0.02+0.15
   .....

[Gaëtan Poirier]

Cool. This helps. Would anything change if I wanted to plot all the data on an x,y plot?

[Gaëtan Poirier]

This is what I have so far, doesn't seem repeat 30000 times, only comes out with one varible in r, x, and y.

 for iter = 1: 30000
    r = rand();
    x = 0.5;
    y = 0;
    if r < 0.02
       y = y * 0.27*r;
    elseif r < 0.02 + 0.15
        x = x -0.139 * r + 0.246 * r;
        y = y + 0.263 * r + 0.224 * r - 0.036;
    elseif r < 0.02 + 0.15 + 0.13
        x = x + 0.17 * r - 0.032 * r;
        y = y + 0.034 * r + 0.739 * r + 0.27;
    elseif r < 0.02 + 0.15 + 0.13 + 0.70
        x = x + 0.781 * r - 0.032 * r;
        y = y + 0.034 * r + 0.1075 + 0.739 * r + 0.27;
    end
end

[Walter Roberson]

x_ = 0.5;
y_ = 0;
for n = 1: 30000
    r = rand();

      if r < 0.02
         y_(n+1) = y_(n) * 0.27*r;
      elseif r < 0.02 + 0.15
          x_(n+1) = x_(n) -0.139 * r + 0.246 * r;
          y_(n+1) = y_(n) + 0.263 * r + 0.224 * r - 0.036;

etc

After all of that you are probably expected to do

scatter(x, y)