Random walk or stepping

hello, i have a 5x5 matrix and i am standing at 2,2 location, now from here i have to take one step and jump to new value. i can take jump in all 4 directions i,e i-1,i+1,j-1,j+1 with equal probability of 0.25, and also i have to update my location for making a counter loop for continous movement inside matrix.how can i code it using randperm ? or any other command available ?

[Walter Roberson]

What should happen if you reach an edge and randomly select to go outside?

randperm() is not going to help you with this. Consider randi()

[Image Analyst]

Is this homework? Just compute the candidate next location. If it's outside of your boundaries, then just get another value, which will most likely be in a different direction and be inside the box.

[Muzaffar Habib]

If i hit the edge i will bounce back to the same location.

[Muzaffar Habib]

Thank You. Much appreciated help. I will try to code that up with randi()

[Walter Roberson]

To "bounce back to the same location" you can use techniques such as

new_x_position = max( min(new_x_position, maximum_x_position), minimum_x_position )

Answer 1

[Eyal Ben-Hur]

Here is a suggestion:

A = zeros(5); % the matrix
p ={2,2}; % initial location
A(p{:}) = 1; % set initial location
N = 20; % no. of steps
for k = 1:N
    s = 1-(rand<0.5)*2; % random +/-
    vh = randi(2); % random vertical or horizontal
    p{vh} = p{vh}+s; % move
    p{vh} = abs(p{vh}-5*(p{vh}==6 || p{vh}==0)); % if outbound, return from the other side
    A = zeros(5); % remove last location
    A(p{:}) = 1; % set new location
end

Since it looks like homwork I leave it to you to understand the details.

[Muzaffar Habib]

Thank U. it did work with some ammendments.