/usr/share/octave/packages/communications-1.2.0/scatterplot.m is in octave-communications-common 1.2.0-2.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
| 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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 | ## Copyright (C) 2003 David Bateman
##
## This program 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.
##
## This program 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
## this program; if not, see <http://www.gnu.org/licenses/>.
## -*- texinfo -*-
## @deftypefn  {Function File} {} scatterplot (@var{x})
## @deftypefnx {Function File} {} scatterplot (@var{x}, @var{n})
## @deftypefnx {Function File} {} scatterplot (@var{x}, @var{n}, @var{off})
## @deftypefnx {Function File} {} scatterplot (@var{x}, @var{n}, @var{off}, @var{str})
## @deftypefnx {Function File} {} scatterplot (@var{x}, @var{n}, @var{off}, @var{str}, @var{h})
## @deftypefnx {Function File} {@var{h} =} scatterplot (@dots{})
##
## Display the scatter plot of a signal. The signal @var{x} can be either in
## one of three forms
##
## @table @asis
## @item A real vector
## In this case the signal is assumed to be real and represented by the vector
## @var{x}. The scatterplot is plotted along the x axis only.
## @item A complex vector
## In this case the in-phase and quadrature components of the signal are
## plotted separately on the x and y axes respectively.
## @item A matrix with two columns
## In this case the first column represents the in-phase and the second the
## quadrature components of a complex signal and are plotted on the x and
## y axes respectively.
## @end table
##
## Each point of the scatter plot is assumed to be separated by @var{n}
## elements in the signal. The first element of the signal to plot is
## determined by @var{off}. By default @var{n} is 1 and @var{off} is 0.
##
## The string @var{str} is a plot style string (example "r+"),
## and by default is the default gnuplot point style.
##
## The figure handle to use can be defined by @var{h}. If @var{h} is not
## given, then the next available figure handle is used. The figure handle
## used in returned on @var{hout}.
## @seealso{eyediagram}
## @end deftypefn
function varargout = scatterplot (x, n, _off, str, h)
  if (nargin < 1 || nargin > 5)
    print_usage ();
  endif
  if (isreal (x))
    if (min (size (x)) == 1)
      signal = "real";
      xr = x(:);
      xi = zeros (size (xr));
    elseif (size (x, 2) == 2)
      signal = "complex";
      xr = x(:,1);
      xi = x(:,2);
    else
      error ("scatterplot: real X must be a vector or a 2-column matrix");
    endif
  else
    signal = "complex";
    if (min (size (x)) != 1)
      error ("scatterplot: complex X must be a vector");
    endif
    xr = real (x(:));
    xi = imag (x(:));
  endif
  if (!length (xr))
    error ("scatterplot: X must not be empty");
  endif
  if (nargin > 1)
    if (! (isscalar (n) && isreal (n) && n == fix (n) && n > 0))
      error ("scatterplot: N must be a positive integer");
    endif
  else
    n = 1;
  endif
  if (nargin > 2)
    if (! (isscalar (_off) && isreal (_off) && _off == fix (_off)
           && _off >= 0 && _off < length (x)))
      error ("scatterplot: OFF must be an integer in the range [0,N-1]");
    endif
    off = _off;
  else
    off = 0;
  endif
  if (nargin > 3)
    if (isempty (str))
      fmt = ".";
    elseif (ischar (str))
      fmt = str;
    else
      error ("scatterplot: STR must be a string");
    endif
  else
    fmt = ".";
  endif
  if (nargin > 4)
    if (isempty (h))
      hout = figure ();
    elseif (isfigure (h) && strcmp (get (h, "tag"), "scatterplot"))
      hout = h;
    else
      error ("scatterplot: H must be a scatterplot figure handle");
    endif
  else
    hout = figure ();
  endif
  set (hout, "tag", "scatterplot");
  set (hout, "name", "Scatter Plot");
  set (0, "currentfigure", hout);
  xr = xr(off+1:n:rows (xr));
  xi = xi(off+1:n:rows (xi));
  plot (xr, xi, fmt);
  if (!strcmp (signal, "complex"))
    ## FIXME: What is the appropriate xrange
    xmax = max (xr);
    xmin = min (xr);
    xran = xmax - xmin
    xmax =  ceil (2 * xmax / xran) / 2 * xran;
    xmin = floor (2 * xmin / xran) / 2 * xran;
    axis ([xmin, xmax, -1, 1]);
  endif
  title ("Scatter plot");
  xlabel ("In-phase");
  ylabel ("Quadrature");
  legend ("off");
  if (nargout > 0)
    varargout{1} = hout;
  endif
endfunction
%!demo
%! n = 200;
%! ovsp = 5;
%! x = 1:n;
%! xi = [1:1/ovsp:n-0.1];
%! y = randsrc (1, n, [1 + i, 1 - i, -1 - i, -1 + i]);
%! yi = interp1 (x, y, xi);
%! noisy = awgn (yi, 15, "measured");
%! h = scatterplot (noisy);
%! hold on;
%! scatterplot (noisy, ovsp, 0, "r+", h);
%% Test input validation
%!error scatterplot ()
%!error scatterplot (1, 2, 3, 4, 5, 6)
%!error scatterplot (1, -1)
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