1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
########################################################################
##
## Copyright (C) 2000-2024 The Octave Project Developers
##
## See the file COPYRIGHT.md in the top-level directory of this
## distribution or <https://octave.org/copyright/>.
##
## This file is part of Octave.
##
## Octave is free software: you can redistribute it and/or modify it
## under the terms of the GNU General Public License as published by
## the Free Software Foundation, either version 3 of the License, or
## (at your option) any later version.
##
## Octave is distributed in the hope that it will be useful, but
## WITHOUT ANY WARRANTY; without even the implied warranty of
## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
## GNU General Public License for more details.
##
## You should have received a copy of the GNU General Public License
## along with Octave; see the file COPYING. If not, see
## <https://www.gnu.org/licenses/>.
##
########################################################################
## -*- texinfo -*-
## @deftypefn {} {[@var{s}, @var{i}] =} sortrows (@var{A})
## @deftypefnx {} {[@var{s}, @var{i}] =} sortrows (@var{A}, @var{c})
## Sort the rows of the matrix @var{A} according to the order of the columns
## specified in @var{c}.
##
## By default (@var{c} omitted, or a particular column unspecified in @var{c})
## an ascending sort order is used. However, if elements of @var{c} are
## negative then the corresponding column is sorted in descending order. If
## the elements of @var{A} are strings then a lexicographical sort is used.
##
## Example: sort by column 2 in descending order, then 3 in ascending order
##
## @example
## @group
## x = [ 7, 1, 4;
## 8, 3, 5;
## 9, 3, 6 ];
## sortrows (x, [-2, 3])
## @result{} 8 3 5
## 9 3 6
## 7 1 4
## @end group
## @end example
##
## @seealso{sort}
## @end deftypefn
function [s, i] = sortrows (A, c)
if (nargin < 1)
print_usage ();
endif
if (nargin == 2)
if (! (isnumeric (c) && isvector (c)))
error ("sortrows: C must be a numeric vector");
elseif (any (c == 0) || any (abs (c) > columns (A)))
error ("sortrows: all elements of C must be in the range [1, columns (A)]");
endif
endif
default_mode = "ascend";
reverse_mode = "descend";
if (issparse (A) || iscell (A))
## FIXME: Eliminate this case once __sort_rows_idx__ is fixed to
## handle sparse matrices.
if (nargin == 1)
i = sort_rows_idx_generic (default_mode, reverse_mode, A);
else
i = sort_rows_idx_generic (default_mode, reverse_mode, A, c);
endif
elseif (nargin == 1)
i = __sort_rows_idx__ (A, default_mode);
elseif (all (c > 0))
i = __sort_rows_idx__ (A(:,c), default_mode);
elseif (all (c < 0))
i = __sort_rows_idx__ (A(:,-c), reverse_mode);
else
## Otherwise, fall back to the old algorithm.
i = sort_rows_idx_generic (default_mode, reverse_mode, A, c);
endif
s = A(i,:);
endfunction
function i = sort_rows_idx_generic (default_mode, reverse_mode, m, c)
if (nargin == 3)
indices = [1:columns(m)]';
mode(1:columns(m)) = {default_mode};
else
for j = 1:length (c)
if (c(j) < 0)
mode{j} = reverse_mode;
else
mode{j} = default_mode;
endif
endfor
indices = abs (c(:));
endif
## Since sort is 'stable' the order of identical elements will be
## preserved, so by traversing the sort indices in reverse order we
## will make sure that identical elements in index i are subsorted by
## index j.
indices = flipud (indices);
mode = flipud (mode');
i = [1:rows(m)]';
for j = 1:length (indices)
M = m(i, indices(j));
if (iscell (M) && ! iscellstr (M))
M = cell2mat (M);
endif
[~, idx] = sort (M, mode{j});
i = i(idx);
endfor
endfunction
%!test
%! m = [1, 1; 1, 2; 3, 6; 2, 7];
%! c = [1, -2];
%! [x, idx] = sortrows (m, c);
%! [sx, sidx] = sortrows (sparse (m), c);
%! assert (x, [1, 2; 1, 1; 2, 7; 3, 6]);
%! assert (idx, [2; 1; 4; 3]);
%! assert (issparse (sx));
%! assert (x, full (sx));
%! assert (idx, sidx);
%!test
%! m = [1, 0, 0, 4];
%! c = 1;
%! [x, idx] = sortrows (m, c);
%! [sx, sidx] = sortrows (sparse (m), c);
%! assert (x, m);
%! assert (idx, 1);
%! assert (issparse (sx));
%! assert (x, full (sx));
%! assert (idx, sidx);
%!test <*42523>
%! C = {1, 2, "filename1";
%! 3, 4, "filename2";
%! 5, 6, "filename3"};
%! C2 = sortrows (C, -1);
%! assert (C2, flipud (C));
## Test input validation
%!error <Invalid call> sortrows ()
%!error sortrows (1, "ascend")
%!error sortrows (1, ones (2,2))
%!error sortrows (1, 0)
%!error sortrows (1, 2)
|
