Mercurial > hg > octave-lyh
changeset 724:86d73993eee2
[project @ 1994-09-21 19:42:34 by jwe]
Initial revision
author | jwe |
---|---|
date | Wed, 21 Sep 1994 19:42:34 +0000 |
parents | 1c072f20b522 |
children | 8fe4c32d09e0 |
files | scripts/plot/hist.m |
diffstat | 1 files changed, 107 insertions(+), 0 deletions(-) [+] |
line wrap: on
line diff
new file mode 100644 --- /dev/null +++ b/scripts/plot/hist.m @@ -0,0 +1,107 @@ +# Copyright (C) 1994 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 2, 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, write to the Free +# Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. + +function [nn, xx] = hist (y, x) + +# usage: [NN, XX] = hist (Y, X) or hist (Y, X) +# +# Produce histogram counts or plots. +# +# With one vector input argument, plot a histogram of the values with +# 10 bins. The range of the histogram bins is determined by the range +# of the data. +# +# Given a second scalar argument, use that as the number of bins. +# +# Given a second vector argument, use that as the centers of the bins, +# with the width of the bins determened from the adjacent values in +# the vector. +# +# Extreme values are lumped in the first and last bins. +# +# With two output arguments, produce the values NN and XX such that +# bar (XX, NN) will plot the histogram. +# +# See also: bar + + if (nargin < 1 || nargin > 2) + error ("usage: [nn, xx] = hist (y, x)"); + endif + + if (is_vector (y)) + max_val = max (y); + min_val = min (y); + else + error ("hist: first argument must be a vector"); + endif + + if (nargin == 1) + n = 10; + delta = (max_val - min_val) / n / 2; + x = linspace (min_val+delta, max_val-delta, n); + cutoff = x + delta; + elseif (nargin == 2) + if (is_scalar (x)) + n = x; + if (n <= 0) + error ("hist: number of bins must be positive"); + endif + delta = (max_val - min_val) / n / 2; + x = linspace (min_val+delta, max_val-delta, n); + cutoff = x + delta; + elseif (is_vector (x)) + tmp = sort (x); + if (any (tmp != x)) + fprintf (stderr, "warning: hist: bin values not sorted on input\n"); + x = tmp; + endif + n = length (x); + cutoff = zeros (1, n-1); + for i = 1:n-1 + cutoff (i) = (x (i) + x (i+1)) / 2; + endfor + else + error ("hist: second argument must be a scalar or a vector"); + endif + endif + + freq = zeros (1, n); + freq (1) = sum (y < cutoff (1)); + for i = 2:n-1 + freq (i) = sum (y >= cutoff (i-1) & y < cutoff (i)); + endfor + freq (n) = sum (y >= cutoff (n-1)); + +# With Octave 1.0, nargout is never zero, so we have to do this: + + nn = freq; + xx = x; + if (nargout != 2) + bar (xx, nn); + endif + +# Once 1.1 is released, we can do this instead: +# +# if (nargout == 2) +# nn = freq; +# xx = x; +# else +# bar (x, freq); +# endif + +endfunction