how to find patterns in an array

Hello

I have a 19*19 array filled with either a 1, -1 or a 0.

I need to find patterns of 5 repeating values next to each other of any value in both row and columns, and then store where the patterns are in an array.

example:

[1 0 0 0 0 0 1 0 -1 ]

and then store where the patterns are in another 19*19 array. As either a row pattern, column pattern or both.

any suggestions on how to do it? I'm completely lost.

[per isakson]

Search the FEX for run length encoding.

Answer 1

[Guillaume]

A loop is probably the simplest and clearest way to do it:

A = randi(3, 20) - 2; %for demo
patternlength = 5;   
pl = patternlength - 1; %actually more useful than patternlength
positions = zeros(size(A)) %output matrix
for col = 1:size(A, 2) - pl
  for row = 1:size(A, 1)- pl
    if all(diff(A(row:row+pl, col)) == 0) || all(diff(A(row, col:col+pl)) == 0)
      positions(row, col) = 1;
    end
  end
end

Answer 2

[Andrei Bobrov]

n = 5;

idxv = find(conv2(double(diff(A) == 0),ones(n-1,1),'same') == n-1);
idxv = idxv - 1;

idxh = find(conv2(double(diff(A,1,2) == 0),ones(1,n-1),'same') == n-1);
idxh = idxh - size(A,1);

Answer 3

[Riley]

Thankyou very much Guillaume, that worked perfectly. Very much appreciated.

Andrei thank you for your time as well.