1 ## Copyright (C) 2007-2012 David Bateman
3 ## This file is part of Octave.
5 ## Octave is free software; you can redistribute it and/or modify it
6 ## under the terms of the GNU General Public License as published by
7 ## the Free Software Foundation; either version 3 of the License, or (at
8 ## your option) any later version.
10 ## Octave is distributed in the hope that it will be useful, but
11 ## WITHOUT ANY WARRANTY; without even the implied warranty of
12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 ## General Public License for more details.
15 ## You should have received a copy of the GNU General Public License
16 ## along with Octave; see the file COPYING. If not, see
17 ## <http://www.gnu.org/licenses/>.
20 ## @deftypefn {Function File} {} compass (@var{u}, @var{v})
21 ## @deftypefnx {Function File} {} compass (@var{z})
22 ## @deftypefnx {Function File} {} compass (@dots{}, @var{style})
23 ## @deftypefnx {Function File} {} compass (@var{h}, @dots{})
24 ## @deftypefnx {Function File} {@var{h} =} compass (@dots{})
26 ## Plot the @code{(@var{u}, @var{v})} components of a vector field emanating
27 ## from the origin of a polar plot. If a single complex argument @var{z} is
28 ## given, then @code{@var{u} = real (@var{z})} and @code{@var{v} = imag
31 ## The style to use for the plot can be defined with a line style @var{style}
32 ## in a similar manner to the line styles used with the @code{plot} command.
34 ## The optional return value @var{h} is a vector of graphics handles to the
35 ## line objects representing the drawn vectors.
39 ## a = toeplitz ([1;randn(9,1)], [1,randn(1,9)]);
44 ## @seealso{polar, quiver, feather, plot}
47 function retval = compass (varargin)
49 [h, varargin, nargin] = __plt_get_axis_arg__ ("compass", varargin{:});
55 elseif (nargin == 1 || (nargin == 2 && ! isnumeric (varargin{2})))
60 elseif (nargin > 1 && isnumeric (varargin{2}))
67 have_line_spec = false;
68 while (ioff <= nargin)
69 arg = varargin{ioff++};
70 if ((ischar (arg) || iscell (arg)) && ! have_line_spec)
71 [linespec, valid] = __pltopt__ ("compass", arg, false);
74 have_line_spec = true;
77 error ("compass: invalid linespec");
80 error ("compass: unrecognized argument");
84 ## Matlab draws compass plots, with the arrow head as one continous
85 ## line, and each arrow separately. This is completely different than
86 ## quiver and quite ugly.
89 xtmp = u .* (1 - arrowsize);
91 ytmp = v .* (1 - arrowsize);
92 x = [zeros(1, n); xend; xtmp - v * arrowsize / 3; xend; ...
93 xtmp + v * arrowsize / 3];
94 y = [zeros(1, n); yend; ytmp + u * arrowsize / 3; yend; ...
95 ytmp - u * arrowsize / 3];
96 [r, p] = cart2pol (x, y);
102 hlist = polar (h, r, p, line_spec);
103 unwind_protect_cleanup
116 %! randn_9x1_data = [-2.555884; 0.394974; -0.191871; -1.147024; 1.355425; -0.437335; -0.014370; -0.941312; 1.240300];
117 %! randn_1x9_data = [1.42934, -1.10821, -1.70404, 0.63357, -0.68337, -1.19771, -0.96502, -1.12810, 0.22457];
118 %! a = toeplitz ([1;randn_9x1_data], [1,randn_1x9_data]);
119 %! compass (eig (a));