Random Walk on 2D Modification

Question

Ege Tunç 2018-12-26

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/437239-random-walk-on-2d-modification

评论： Ege Tunç 2019-1-6

采纳的回答： Walter Roberson

在 MATLAB Online 中打开

I have 2D random walk code part for neutrons. However, the code includes some conditions, 2 of them are:

on the next step the neutron cannot step back, but only forward, left or right ,
the probability to go forward is twice more than changing a direction

I could not modified the code for "cannot step back" part. Also, i have no idea how to make the probability is doubled for not changing direction. Since, if it's once changed direction it has the change to go straight forward is still doubled.

Here's the code:

clc;
clearvars;
N = 100; % Length of the x-axis, also known as the length of the random walks.
M = 100; % The amount of random walks.
x_t(1) = 0;
y_t(1) = 0;
for m=1:M
  for n = 1:N 
    A = sign(randn); 
    x_t(n+1) = x_t(n) + A;
    A = sign(randn); 
    y_t(n+1) = y_t(n) + A;
  end
  plot(x_t, y_t);
  hold on
end
grid on;
set(gcf, 'Units', 'Normalized', 'Outerposition', [0, 0.05, 1, 0.95]);
axis square;

4 个评论
显示 2更早的评论隐藏 2更早的评论

Walter Roberson 2019-1-6

"close" means make it invisible to the public, such as for a question that needs clarification from the author.

Ege Tunç 2019-1-6

okay, i opened it. sorry for my misunderstanding

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2018-12-26

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/437239-random-walk-on-2d-modification#answer_353942

编辑：Walter Roberson 2018-12-26

在 MATLAB Online 中打开

dd = randi(4)
  for ss = 1:500
    rr = rand;
   if rr < 1/4
    dd = 1+mod(dd,4)   %next higher direction
  elseif rr < 1/2
     dd = 1+mod(dd-2,4)     %next lower direction
  end    % 50 percent stays same direction 
  if dd==1
   yy=yy+1;     %north 
  elseif dd==2
    xx=xx+1;    %east
  elseif dd==3
    yy=yy-1;     %south
   else
     xx=xx-1;    %west
   end
   plot here probably 
  end