function [cell_indices, unique_values]=cosmo_index_unique(values)
% index unique (combinations of) elements
%
% [cell_indices, unique_values]=cosmo_index_unique(values)
%
% Input:
% values either:
% - cell with K elements, each of which must be
% either a vector with M elements or a cell with
% M strings (each element in each cell is treated
% as a row); or
% - MxK matrix
%
% Returns:
% cell_indices Ux1 cell, if along the input there are U unique
% combinations of values (element-wise). The K-th
% element has U_K indices in the range 1:M indicating
% the rows in the input have the same value
% unique_values either:
% - Kx1 cell, each with U elements, containing the
% unique combinations of values of the input
% [if the input is a cell]; or
% - UxK cell, containing the unique rows in the input
%
% Examples:
% [i,u]=cosmo_index_unique({[3 2 2 2 1],[3 2 3 3 3]});
% cosmo_disp(i);
% %|| { [ 5 ]
% %|| [ 2 ]
% %|| [ 3
% %|| 4 ]
% %|| [ 1 ] }
% cosmo_disp(u);
% %|| { [ 1 [ 3
% %|| 2 2
% %|| 2 3
% %|| 3 ] 3 ] }
%
% % the same operation in matrix operation (input is transposed)
% [i,u]=cosmo_index_unique([3 2 2 2 1;3 2 3 3 3]');
% cosmo_disp(i);
% %|| { [ 5 ]
% %|| [ 2 ]
% %|| [ 3
% %|| 4 ]
% %|| [ 1 ] }
% cosmo_disp(u);
% %|| [ 1 3
% %|| 2 2
% %|| 2 3
% %|| 3 3 ]
%
% % it also works if (some of the) input contains cell strings
% [i,u]=cosmo_index_unique({{'ccc','bb','bb','bb','a'},...
% [4 3 4 4 4]});
% cosmo_disp(i);
% %|| { [ 5 ]
% %|| [ 2 ]
% %|| [ 3
% %|| 4 ]
% %|| [ 1 ] }
% cosmo_disp(u);
% %|| { { 'a' [ 4
% %|| 'bb' 3
% %|| 'bb' 4
% %|| 'ccc' } 4 ] }
%
% # For CoSMoMVPA's copyright information and license terms, #
% # see the COPYING file distributed with CoSMoMVPA. #
