[37] | 1 | function [b,ndx,pos] = unique(a,flag) |
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| 2 | % Ripped unique |
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| 3 | % For safety, we use 7.0 (6.1 sort differently...) |
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| 4 | |
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| 5 | nIn = nargin; |
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| 6 | |
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| 7 | if nIn < 1 |
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| 8 | error('MATLAB:UNIQUE:NotEnoughInputs', 'Not enough input arguments.'); |
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| 9 | elseif nIn > 2 |
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| 10 | error('MATLAB:UNIQUE:TooManyInputs', 'Too many input arguments.'); |
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| 11 | end |
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| 12 | |
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| 13 | if nIn == 1 |
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| 14 | flag = []; |
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| 15 | end |
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| 16 | |
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| 17 | rows = size(a,1); |
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| 18 | cols = size(a,2); |
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| 19 | |
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| 20 | rowvec = (rows == 1) & (cols > 1); |
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| 21 | |
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| 22 | numelA = prod(size(a)); |
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| 23 | nOut = nargout; |
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| 24 | |
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| 25 | if isempty(flag) |
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| 26 | |
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| 27 | % Handle empty: no elements. |
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| 28 | |
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| 29 | if (numelA == 0) |
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| 30 | % Predefine b to be of the correct type. |
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| 31 | b = a([]); |
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| 32 | if max(size(a)) > 0 |
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| 33 | b = reshape(b,0,1); |
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| 34 | ndx = zeros(0,1); |
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| 35 | pos = zeros(0,1); |
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| 36 | else |
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| 37 | ndx = []; |
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| 38 | pos = []; |
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| 39 | end |
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| 40 | return |
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| 41 | |
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| 42 | elseif (numelA == 1) |
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| 43 | % Scalar A: return the existing value of A. |
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| 44 | b = a; ndx = 1; pos = 1; |
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| 45 | return |
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| 46 | |
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| 47 | % General handling. |
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| 48 | else |
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| 49 | |
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| 50 | % Convert to columns |
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| 51 | a = a(:); |
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| 52 | |
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| 53 | % Convert to double array for purposes of faster sorting. |
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| 54 | % Additionally, UNIQUE calls DIFF, which requires double input. |
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| 55 | |
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| 56 | whichclass = class(a); |
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| 57 | isdouble = strcmp(whichclass,'double'); |
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| 58 | |
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| 59 | if ~isdouble |
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| 60 | a = double(a); |
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| 61 | end |
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| 62 | |
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| 63 | % Sort if unsorted. Only check this for long lists. |
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| 64 | |
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| 65 | checksortcut = 1000; |
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| 66 | |
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| 67 | if numelA <= checksortcut | ~(issorted(a)) |
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| 68 | if nOut <= 1 |
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| 69 | b = sort(a); |
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| 70 | else |
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| 71 | [b,ndx] = sort(a); |
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| 72 | end |
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| 73 | else |
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| 74 | b = a; |
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| 75 | if nOut > 1 |
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| 76 | ndx = (1:numelA)'; % If presorted, indices are 1,2,3,... |
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| 77 | end |
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| 78 | end |
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| 79 | |
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| 80 | % d indicates the location of non-matching entries. |
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| 81 | |
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| 82 | db = diff(b); |
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| 83 | |
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| 84 | % Since DIFF returns NaN in both Inf and NaN cases, |
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| 85 | % use slower method of detection if NaN's detected in DIFF(b). |
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| 86 | % After sort, Infs or NaNs will be at ends of list only. |
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| 87 | |
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| 88 | if (isnan(db(1)) | isnan(db(numelA-1))) |
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| 89 | d = b(1:numelA-1) ~= b(2:numelA); |
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| 90 | else |
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| 91 | d = db ~= 0; |
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| 92 | end |
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| 93 | |
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| 94 | d(numelA,1) = 1; % Final element is always member of unique list. |
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| 95 | |
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| 96 | b = b(d); % Create unique list by indexing into sorted list. |
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| 97 | |
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| 98 | if nOut == 3 |
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| 99 | pos = cumsum([1;full(d)]); % Lists position, starting at 1. |
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| 100 | pos(numelA+1) = []; % Remove extra element introduced by d. |
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| 101 | pos(ndx) = pos; % Re-reference POS to indexing of SORT. |
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| 102 | end |
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| 103 | |
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| 104 | % Create indices if needed. |
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| 105 | if nOut > 1 |
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| 106 | ndx = ndx(d); |
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| 107 | end |
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| 108 | |
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| 109 | % Re-convert to correct output data type using FEVAL. |
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| 110 | if ~isdouble |
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| 111 | b = feval(whichclass,b); |
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| 112 | end |
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| 113 | end |
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| 114 | |
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| 115 | % If row vector, return as row vector. |
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| 116 | if rowvec |
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| 117 | b = b.'; |
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| 118 | if nOut > 1 |
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| 119 | ndx = ndx.'; |
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| 120 | if nOut > 2 |
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| 121 | pos = pos.'; |
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| 122 | end |
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| 123 | end |
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| 124 | end |
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| 125 | |
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| 126 | else % 'rows' case |
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| 127 | if ~strcmpi(flag,'rows') |
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| 128 | error('MATLAB:UNIQUE:UnknownFlag', 'Unknown flag.'); |
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| 129 | end |
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| 130 | |
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| 131 | % Handle empty: no rows. |
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| 132 | |
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| 133 | if (rows == 0) |
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| 134 | % Predefine b to be of the correct type. |
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| 135 | b = a([]); |
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| 136 | ndx = []; |
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| 137 | pos = []; |
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| 138 | b = reshape(b,0,cols); |
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| 139 | if cols > 0 |
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| 140 | ndx = reshape(ndx,0,1); |
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| 141 | end |
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| 142 | return |
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| 143 | |
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| 144 | % Handle scalar: one row. |
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| 145 | |
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| 146 | elseif (rows == 1) |
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| 147 | b = a; ndx = 1; pos = 1; |
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| 148 | return |
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| 149 | end |
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| 150 | |
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| 151 | % General handling. |
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| 152 | % Conversion to double not done: SORTROWS is slower for doubles |
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| 153 | % than other types. |
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| 154 | |
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| 155 | if nOut > 1 |
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| 156 | [b,ndx] = sortrows(a); |
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| 157 | else |
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| 158 | b = sortrows(a); |
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| 159 | end |
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| 160 | |
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| 161 | % d indicates the location of non-matching entries. |
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| 162 | |
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| 163 | d = b(1:rows-1,:)~=b(2:rows,:); |
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| 164 | |
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| 165 | % d = 1 if differences between rows. d = 0 if the rows are equal. |
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| 166 | |
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| 167 | d = any(d,2); |
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| 168 | d(rows,1) = 1; % Final row is always member of unique list. |
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| 169 | |
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| 170 | b = b(d,:); % Create unique list by indexing into sorted list. |
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| 171 | |
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| 172 | % Create position mapping vector using CUMSUM. |
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| 173 | |
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| 174 | if nOut == 3 |
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| 175 | pos = cumsum([1;full(d)]); % Lists position, starting at 1. |
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| 176 | pos(rows+1) = []; % Remove extra element introduced by d. |
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| 177 | pos(ndx) = pos; % Re-reference POS to indexing of SORT. |
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| 178 | end |
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| 179 | |
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| 180 | % Create indices if needed. |
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| 181 | if nOut > 1 |
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| 182 | ndx = ndx(d); |
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| 183 | end |
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| 184 | end |
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| 185 | |
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| 186 | |
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