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25
26## -*- texinfo -*-
27## @deftypefn  {} {} run_count (@var{x}, @var{n})
28## @deftypefnx {} {} run_count (@var{x}, @var{n}, @var{dim})
29## Count the upward runs along the first non-singleton dimension of @var{x}
30## of length 1, 2, @dots{}, @var{n}-1 and greater than or equal to @var{n}.
31##
32## If the optional argument @var{dim} is given then operate along this
33## dimension.
34## @seealso{runlength}
35## @end deftypefn
36
37function retval = run_count (x, n, dim)
38
39  if (nargin != 2 && nargin != 3)
40    print_usage ();
41  endif
42
43  if (! (isnumeric (x) || islogical (x)))
44    error ("run_count: X must be a numeric vector or matrix");
45  endif
46
47  if (!(isscalar (n) && n == fix (n) && n > 0))
48    error ("run_count: N must be a positive integer");
49  endif
50
51  nd = ndims (x);
52  sz = size (x);
53  if (nargin != 3)
54    ## Find the first non-singleton dimension.
55    (dim = find (sz > 1, 1)) || (dim = 1);
56  else
57    if (!(isscalar (dim) && dim == fix (dim))
58        || !(1 <= dim && dim <= nd))
59      error ("run_count: DIM must be an integer and a valid dimension");
60    endif
61  endif
62
63  ## Algorithm works on rows.  Permute array if necessary, ipermute back at end
64  if (dim != 1)
65    perm = [1 : nd];
66    perm(1) = dim;
67    perm(dim) = 1;
68    x = permute (x, perm);
69  endif
70
71  sz = size (x);
72  idx = cell ();
73  for i = 1 : nd
74    idx{i} = 1 : sz(i);
75  endfor
76  c = sz(1);
77  tmp = zeros ([c + 1, sz(2 : end)]);
78  infvec = Inf ([1, sz(2 : end)]);
79
80  ind = find (diff ([infvec; x; -infvec]) < 0);
81  tmp(ind(2:end) - 1) = diff (ind);
82  tmp = tmp(idx{:});
83
84  sz(1) = n;
85  retval = zeros (sz);
86  for k = 1 : (n-1)
87    idx{1} = k;
88    retval(idx{:}) = sum (tmp == k);
89  endfor
90  idx{1} = n;
91  retval(idx{:}) = sum (tmp >= n);
92
93  if (dim != 1)
94    retval = ipermute (retval, perm);
95  endif
96
97endfunction
98
99
100%!assert (run_count (magic (3), 4), [1,0,1;1,0,1;0,1,0;0,0,0])
101%!assert (run_count (magic (3), 4, 2), [1,0,1;1,0,1;0,1,0;0,0,0]')
102%!assert (run_count (5:-1:1, 5), [5, 0, 0, 0, 0])
103%!assert (run_count (ones (3), 4), [0,0,0;0,0,0;1,1,1;0,0,0])
104
105## Test input validation
106%!error run_count ()
107%!error run_count (1)
108%!error run_count (1, 2, 3, 4)
109%!error run_count ({1, 2}, 3)
110%!error run_count (['A'; 'A'; 'B'], 3)
111%!error run_count (1:5, ones (2,2))
112%!error run_count (1:5, 1.5)
113%!error run_count (1:5, -2)
114%!error run_count (1:5, 3, ones (2,2))
115%!error run_count (1:5, 3, 1.5)
116%!error run_count (1:5, 3, 0)
117