MATLAB: Help with the unique function

MATLABmatlab function

The unique function fails to sort the following redundancy;

K>> b

b = [15.0000 15.0000 15.0000 -5.0000 15.0000]

K>> unique(b)

ans = -5.0000 15.0000 15.0000 15.0000 15.0000

but when the vector is made up of integers:

a = [15 15 15 15 -5 15]

K>> unique(ans)

ans = -5 15

How can I solve this problem?

If you look at the output of

b - 15

You'll see that some (or all) these 15.0000 are not actually 15.0000 but something very close to it but different from each other.

The solution: use uniquetol:

uniquetol(b);  %you can specify the tolerance as well.

Assuming your matrix is A, the following code returns what you want as B.

B = sortrows(A,[1 4]);
idx = [false; diff(B(:,1)) == 0];
B(idx,:) = [];

Nevermind. It's a rounding issue. Doing

round(data,3);

first fixed it.