How to modify my 1D random walk sequence to a reflecting type random walk?

Question

DEVANAND 2014-8-17

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/151247-how-to-modify-my-1d-random-walk-sequence-to-a-reflecting-type-random-walk

评论： Image Analyst 2014-8-18

采纳的回答： Image Analyst

rw.jpg

在 MATLAB Online 中打开

I have a sequence 'x' generated as below (for simulating 1D random walk):

r=rand(1,1000);
r(r>.5)=1;
r(r<=.5)=-1;
x=cumsum(r);

If I consider 2 values in the sequence , say +10 and -10, then I would like to reflect the sequence 'x' when it reaches those values. How to achieve this?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Image Analyst 2014-8-17

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/151247-how-to-modify-my-1d-random-walk-sequence-to-a-reflecting-type-random-walk#answer_148877

在 MATLAB Online 中打开

Try this

logicalIndexes = x > 10
x(logicalIndexes) = 10 - x(logicalIndexes);
logicalIndexes = x < -10
x(logicalIndexes) = -10 - x(logicalIndexes);

2 个评论
显示无隐藏无

DEVANAND 2014-8-18

Sorry this is not what I wanted. When I checked it shows wrong output.

Image Analyst 2014-8-18

在 MATLAB Online 中打开

Try this. Every time it's at 10 and tries to go to 11, it goes to 9 instead, so it's "reflected" about 10. Same for -10.

clc;    % Clear the command window.
close all;  % Close all figures (except those of imtool.)
clear;  % Erase all existing variables. Or clearvars if you want.
workspace;  % Make sure the workspace panel is showing.
fontSize = 22;
r = 2*randi(2, 1, 1000)- 3;
x(1) = 0;
for index = 2 : length(r)
  x(index) = x(index-1) + r(index);
  if x(index) > 10
    x(index) = 9;
  elseif x(index) < -10
    x(index) = -9;
  end
end
plot(x, 'b-', 'LineWidth', 2);
% Enlarge figure to full screen.
set(gcf, 'Units', 'Normalized', 'OuterPosition', [0 0 1 1]);
grid on;
ylabel('x', 'FontSize', fontSize);
xlabel('Step Number', 'FontSize', fontSize);