--- /dev/null
+## Copyright (C) 1994-2012 John W. Eaton
+##
+## 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
+## <http://www.gnu.org/licenses/>.
+
+## -*- texinfo -*-
+## @deftypefn {Function File} {} hist (@var{y})
+## @deftypefnx {Function File} {} hist (@var{y}, @var{x})
+## @deftypefnx {Function File} {} hist (@var{y}, @var{nbins})
+## @deftypefnx {Function File} {} hist (@var{y}, @var{x}, @var{norm})
+## @deftypefnx {Function File} {[@var{nn}, @var{xx}] =} hist (@dots{})
+## @deftypefnx {Function File} {[@dots{}] =} hist (@dots{}, @var{prop}, @var{val})
+##
+## Produce histogram counts or plots.
+##
+## With one vector input argument, @var{y}, plot a histogram of the values
+## with 10 bins. The range of the histogram bins is determined by the
+## range of the data. With one matrix input argument, @var{y}, plot a
+## histogram where each bin contains a bar per input column.
+##
+## Given a second vector argument, @var{x}, use that as the centers of
+## the bins, with the width of the bins determined from the adjacent
+## values in the vector.
+##
+## If scalar, the second argument, @var{nbins}, defines the number of bins.
+##
+## If a third argument is provided, the histogram is normalized such that
+## the sum of the bars is equal to @var{norm}.
+##
+## Extreme values are lumped in the first and last bins.
+##
+## With two output arguments, produce the values @var{nn} and @var{xx} such
+## that @code{bar (@var{xx}, @var{nn})} will plot the histogram.
+##
+## The histogram's appearance may be modified by specifying property/value
+## pairs, @var{prop} and @var{val} pairs. For example the face and edge
+## color may be modified.
+##
+## @example
+## @group
+## hist (randn (1, 100), 25, "facecolor", "r", "edgecolor", "b");
+## @end group
+## @end example
+##
+## @noindent
+## The histograms colors also depend upon the colormap.
+##
+## @example
+## @group
+## hist (rand (10, 3));
+## colormap (summer ());
+## @end group
+## @end example
+##
+## @seealso{bar}
+## @end deftypefn
+
+## Author: jwe
+
+function [nn, xx] = hist (y, varargin)
+
+ if (nargin < 1)
+ print_usage ();
+ endif
+
+ arg_is_vector = isvector (y);
+
+ if (rows (y) == 1)
+ y = y(:);
+ endif
+
+ if (isreal (y))
+ max_val = max (y(:));
+ min_val = min (y(:));
+ else
+ error ("hist: first argument must be real valued");
+ endif
+
+ iarg = 1;
+ if (nargin == 1 || ischar (varargin{iarg}))
+ n = 10;
+ x = [0.5:n]'/n;
+ x = x * (max_val - min_val) + ones(size(x)) * min_val;
+ else
+ ## nargin is either 2 or 3
+ x = varargin{iarg++};
+ if (isscalar (x))
+ n = x;
+ if (n <= 0)
+ error ("hist: number of bins must be positive");
+ endif
+ x = [0.5:n]'/n;
+ x = x * (max_val - min_val) + ones (size (x)) * min_val;
+ elseif (isreal (x))
+ if (isvector (x))
+ x = x(:);
+ endif
+ tmp = sort (x);
+ if (any (tmp != x))
+ warning ("hist: bin values not sorted on input");
+ x = tmp;
+ endif
+ else
+ error ("hist: second argument must be a scalar or a vector");
+ endif
+ endif
+
+ ## Avoid issues with integer types for x and y
+ x = double (x);
+ y = double (y);
+
+ cutoff = (x(1:end-1,:) + x(2:end,:)) / 2;
+ n = rows (x);
+ y_nc = columns (y);
+ if (n < 30 && columns (x) == 1)
+ ## The following algorithm works fastest for n less than about 30.
+ chist = zeros (n+1, y_nc);
+ for i = 1:n-1
+ chist(i+1,:) = sum (y <= cutoff(i));
+ endfor
+ chist(n+1,:) = sum (! isnan (y));
+ else
+ ## The following algorithm works fastest for n greater than about 30.
+ ## Put cutoff elements between boundaries, integrate over all
+ ## elements, keep totals at boundaries.
+ [s, idx] = sort ([y; repmat(cutoff, 1, y_nc)]);
+ len = rows (y);
+ chist = cumsum (idx <= len);
+ chist = [(zeros (1, y_nc));
+ (reshape (chist(idx > len), rows (cutoff), y_nc));
+ (chist(end,:) - sum (isnan (y)))];
+ endif
+
+ freq = diff (chist);
+
+ if (nargin > 2 && ! ischar (varargin{iarg}))
+ ## Normalise the histogram.
+ norm = varargin{iarg++};
+ freq = freq / rows (y) * norm;
+ endif
+
+ if (nargout > 0)
+ if (arg_is_vector)
+ nn = freq';
+ xx = x';
+ else
+ nn = freq;
+ xx = x;
+ endif
+ elseif (size (freq, 2) != 1)
+ bar (x, freq, 0.8, varargin{iarg:end});
+ else
+ bar (x, freq, 1.0, varargin{iarg:end});
+ endif
+
+endfunction
+
+%!test
+%! [nn,xx]=hist([1:4],3);
+%! assert(xx, [1.5,2.5,3.5]);
+%! assert(nn, [2,1,1]);
+%!test
+%! [nn,xx]=hist([1:4]',3);
+%! assert(xx, [1.5,2.5,3.5]);
+%! assert(nn, [2,1,1]);
+%!test
+%! [nn,xx]=hist([1 1 1 NaN NaN NaN 2 2 3],[1 2 3]);
+%! assert(xx, [1,2,3]);
+%! assert(nn, [3,2,1]);
+%!test
+%! [nn,xx]=hist([[1:4]',[1:4]'],3);
+%! assert(xx, [1.5;2.5;3.5]);
+%! assert(nn, [[2,1,1]',[2,1,1]']);
+%!assert(hist(1,1),1);
+%!test
+%! for n = [10, 30, 100, 1000]
+%! assert(sum(hist([1:n], n)), n);
+%! assert(sum(hist([1:n], [2:n-1])), n);
+%! assert(sum(hist([1:n], [1:n])), n);
+%! assert(sum(hist([1:n], 29)), n);
+%! assert(sum(hist([1:n], 30)), n);
+%! endfor
+%!test
+%! assert (size (hist(randn(750,240), 200)), [200,240]);
git://git.creatis.insa-lyon.fr / CreaPhase.git / blobdiff