MATLAB: Finding equal rows in a matrix

comparing floating point numbers

I have a problem with finding equal elements in array. I searched and read all post about it, but i couldn't solve my problem. I have a 20×2 double array, t=0 and n=20. I want to find equal elements and result their row number. But i didn't. My code is at below :
   for i=1:n
     for j=2:n
         if neigbor(i,:,t)==neigbor(j,:,t)
             g(i,:)=i;
         else
             g(i,:)=0;
         end
     end
  end
I also tried unique and ismember functions. Like this:
[x,y,z] = unique(neigbor,'rows');
Not further. My neigbor(i,:,t) is at below, in this sample i want to see 8,9 and 10 row numbers.
neigbor =
       -4.2500   -3.5000
       -3.5000   -2.7500
       -2.7500   -2.0000
       -2.0000   -1.2500
       -1.2500   -0.5000
       -0.5000    0.2500
        0.2500    1.0000
        1.0000    1.7500
        1.0000    1.7500
        1.0000    1.7500
        1.7500    2.5000
        2.5000    3.2500
        3.2500    4.0000
        4.0000    4.7500
        4.7500    5.5000
        5.5000    6.2500
        6.2500    7.0000
        7.0000    7.7500
        7.7500    8.5000
        8.5000    9.2500
Where is my mistake? Can you make a suggestion or give any hint? If I repeat this question, sorry for that.

Best Answer

This works. It could be made more compact but I wanted you to see each step of the way.
neigbor =[...
  -4.2500   -3.5000
  -3.5000   -2.7500
  -2.7500   -2.0000
  -2.0000   -1.2500
  -1.2500   -0.5000
  -0.5000    0.2500
  0.2500    1.0000
  1.0000    1.7500
  1.0000    1.7500
  1.0000    1.7500
  1.7500    2.5000
  2.5000    3.2500
  3.2500    4.0000
  4.0000    4.7500
  4.7500    5.5000
  5.5000    6.2500
  6.2500    7.0000
  7.0000    7.7500
  7.7500    8.5000
  8.5000    9.2500]
differencesFromRowAbove = diff(neigbor)
allZeroRows = all(differencesFromRowAbove == 0, 2)
rowsToKeep = find(allZeroRows)
% Add on first one
rowsToKeep = [rowsToKeep(1); rowsToKeep+1]
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