MATLAB: Use of 2012 unique version with Matlab 2011a possible

matlab versionunique

Would it be possible to use the new version of "unique" in an older matlab version? I wrote some code and used "unique" with the 'stable' option and I need to run this code on another computer with Matlab 2011a.

If it's possible: Which files would I need to copy?

Best Answer

This would not be permitted under the license agreement, and would not be technically supported.

Related Solutions

MATLAB: Interpolation vector with a lot of duplicate values code on R2010a

You can emulate the modern unique('stable') by:

function [AA, AI, BI] = UniqueStable(A)
% Equivalent to: unique(A(:), 'stable')
% Inptus: single, double (U)INT8/16/31/64, char
% Author: Jan Simon, Heidelberg 2017, License: CC BY-SA 3.0
nA = numel(A);
if nA == 0
   AA = [];
   AI = [];
   BI = [];
else
   [As, SV] = sort(A(:));
   if nargout == 1
      UV(SV) = ([true; diff(As) ~= 0]);
      AA     = A(UV);
     else  % Indices requested:
        UV      = ([true; diff(As) ~= 0]);
        UVs(SV) = UV;
        AI      = find(UVs).';
        AA      = A(UVs);
        % Complex creation of BI such that AA(BI) == A:
        v      = zeros(nA, 1);
        v(AI)  = 1:length(AI);    % Sequence related to AA
        vs     = v(SV);           % Sorted like A
        vf     = vs(vs ~= 0);     % Just the filled entries
        BI     = zeros(nA, 1);    % Pre-allocate
        BI(SV) = vf(cumsum(UV));  % Inflate multiple elements
     end
  end

[EDITED] Note: This is even faster than Matlab's unqiue(x, 'stable'):

x  = rand(1, 1e3);
f1 = @() UniqueStable(x);
f2 = @() unique(x, 'stable');
timeit(f1, 3)
timeit(f2, 3)
%    0.000191363010829893
%    0.000382956117288057

For 1e6 elements:

%    0.358884703612193
%    0.490294384698773

A version for cell strings: https://www.mathworks.com/matlabcentral/answers/45320-faster-function-than-unique-for-cell-arrays

MATLAB: Row indices of an array which is a subset of another array

Maybe your mean:

b = cat(2, [ 7;6;5;4;4;3;2;1;20;19;18;17;16;20;21;22;23], ...
           [30;29;28;27;8;9;10;11;8;12;13;14;15;27;26;25;24]);
a = [20; 21; 22; 23];
[~, Result] = ismember(a, b(:, 1), 'legacy');
if ~any(Result)
  [~, Result] = ismember(a, b(:, 2), 'legacy');
end

But I detest the 'legacy' flag. Even the documentation is vague about its meaning:

 preserves the behavior of the ismember function from R2012b and prior
 releases using any of the input arguments in previous syntaxes.

Without knowing what the prior (to what?!) releases did, this description is useless. There is no way to let unique search for 'stable' and 'last' at the same time.

Therefore I'd prefer:

b = cat(2, [ 7;6;5;4;4;3;2;1;20;19;18;17;16;20;21;22;23], ...
           [30;29;28;27;8;9;10;11;8;12;13;14;15;27;26;25;24]);
[B1, Index1] = uniqueStableLast(b);
[B2, Index2] = uniqueStableLast(b);
[~, loc] = ismember(a, B1);
if any(loc)
   Result = Index1(loc);
else
  [~, loc] = ismember(a, B2);
   Result  = Index2(loc);
end

With:

function [B, AI, BI] = uniqueStableLast(A)
nA = numel(A);
if nA
   % Stable with choosing the last element:
   [As, SV] = sort(A(:), 'descend');
   As       = As(nA:-1:1);
   SV       = SV(nA:-1:1);
     % Stable with the first element would be:
     % [As, SV] = sort(A(:));
     if nargout == 1
       UV(SV) = [false; diff(As) ~= 0];
       B      = A(UV);
     else  % Indices requested:
        UV      = [false; diff(As)] ~= 0];
        UVs(SV) = UV;
        AI      = find(UVs);
        B       = A(UVs);
        if nargout == 3 
          % Complex creation of BI such that BB(BI) == A:
          v      = zeros(1, nA);
          v(AI)  = 1:length(AI);    % Sequence related to BB
          vs     = v(SV);           % Sorted like A
          vf     = vs(vs ~= 0);     % Just the filled entries
          BI(SV) = vf(cumsum(UV));  % Inflate multiple elements
        end
     end
  else
     B  = [];
     AI = [];
     BI = [];
  end

By the way: This is even faster than Matlab's unique('stable').

Best Answer

Related Solutions

MATLAB: Interpolation vector with a lot of duplicate values code on R2010a

MATLAB: Row indices of an array which is a subset of another array

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