Uniquetol retrieving index that is not removed

Hi all,

When I am using uniquetol in Matlab, how can I retrieve the row indices that are not removed, which previously have the same values to those that were removed by uniquetol?

e.g.

a=[1 2; 3 4; 1 2; 5 7]

uniquetol gives =[1 2; 3 4; 5 7], and using setdiff for the retained elements IA I can get --> 3, the removed row index.

But how can I get 1, the row index that is not removed?

Thanks in advance

Answer 1

[Walter Roberson]

[~, ~, uidx] = uniquetol(a, 'ByRows', true);
counts = accumarray(uidx, 1);
find(counts>1)