Mercurial > octave
view scripts/plot/draw/streamline.m @ 30564:796f54d4ddbf stable
update Octave Project Developers copyright for the new year
In files that have the "Octave Project Developers" copyright notice,
update for 2021.
In all .txi and .texi files except gpl.txi and gpl.texi in the
doc/liboctave and doc/interpreter directories, change the copyright
to "Octave Project Developers", the same as used for other source
files. Update copyright notices for 2022 (not done since 2019). For
gpl.txi and gpl.texi, change the copyright notice to be "Free Software
Foundation, Inc." and leave the date at 2007 only because this file
only contains the text of the GPL, not anything created by the Octave
Project Developers.
Add Paul Thomas to contributors.in.
author | John W. Eaton <jwe@octave.org> |
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date | Tue, 28 Dec 2021 18:22:40 -0500 |
parents | 7854d5752dd2 |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2019-2022 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or <https://octave.org/copyright/>. ## ## 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 ## <https://www.gnu.org/licenses/>. ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {} streamline (@var{x}, @var{y}, @var{z}, @var{u}, @var{v}, @var{w}, @var{sx}, @var{sy}, @var{sz}) ## @deftypefnx {} {} streamline (@var{u}, @var{v}, @var{w}, @var{sx}, @var{sy}, @var{sz}) ## @deftypefnx {} {} streamline (@dots{}, @var{options}) ## @deftypefnx {} {} streamline (@var{hax}, @dots{}) ## @deftypefnx {} {@var{h} =} streamline (@dots{}) ## Plot streamlines of 2-D or 3-D vector fields. ## ## Plot streamlines of a 2-D or 3-D vector field given by ## @code{[@var{u}, @var{v}]} or @code{[@var{u}, @var{v}, @var{w}]}. The vector ## field is defined over a rectangular grid given by @code{[@var{x}, @var{y}]} ## or @code{[@var{x}, @var{y}, @var{z}]}. The streamlines start at the seed ## points @code{[@var{sx}, @var{sy}]} or @code{[@var{sx}, @var{sy}, @var{sz}]}. ## ## The input parameter @var{options} is a 2-D vector of the form ## @code{[@var{stepsize}, @var{max_vertices}]}. The first parameter ## specifies the step size used for trajectory integration (default 0.1). A ## negative value is allowed which will reverse the direction of integration. ## The second parameter specifies the maximum number of segments used to ## create a streamline (default 10,000). ## ## If the first argument @var{hax} is an axes handle, then plot into this axes, ## rather than the current axes returned by @code{gca}. ## ## The optional return value @var{h} is a graphics handle to the hggroup ## comprising the field lines. ## ## Example: ## ## @example ## @group ## [x, y] = meshgrid (-1.5:0.2:2, -1:0.2:2); ## u = - x / 4 - y; ## v = x - y / 4; ## streamline (x, y, u, v, 1.7, 1.5); ## @end group ## @end example ## ## @seealso{stream2, stream3, streamribbon, streamtube, ostreamtube} ## @end deftypefn function h = streamline (varargin) [hax, varargin, nargin] = __plt_get_axis_arg__ ("streamline", varargin{:}); if (nargin == 0) print_usage (); endif nd = ndims (varargin{1}); if (nd > 3) error ("streamline: input data must be 2-D or 3-D"); endif if (isempty (hax)) hax = gca (); else hax = hax(1); endif h = []; if (nd == 2) xy = stream2 (varargin{:}); for i = 1 : length (xy) sl = xy{i}; if (! isempty (sl)) htmp = line (hax, "xdata", sl(:, 1), "ydata", sl(:, 2), "color", "b"); h = [h; htmp]; endif endfor else xyz = stream3 (varargin{:}); for i = 1 : length (xyz) sl = xyz{i}; if (! isempty (sl)) htmp = line (hax, "xdata", sl(:, 1), "ydata", sl(:, 2), "zdata", sl(:, 3), "color", "b"); h = [h; htmp]; endif endfor endif endfunction %!demo %! clf; %! [x, y] = meshgrid (-2:0.5:2); %! u = - y - x / 2; %! v = x - y / 2; %! [sx, sy] = meshgrid (-2:2:2); %! h = streamline (x, y, u, v, sx, sy); %! set (h, "color", "r"); %! hold on; %! quiver (x, y, u, v); %! scatter (sx(:), sy(:), 20, "filled", "o", "markerfacecolor", "r"); %! title ("Spiral Sink"); %! grid on; %! axis equal; %!demo %! clf; %! [x, y, z] = meshgrid (-3:3); %! u = - x / 2 - y; %! v = x - y / 2; %! w = - z; %! [sx, sy, sz] = meshgrid (3, 0:1.5:1.5, 0:1.5:3); %! h = streamline (x, y, z, u, v, w, sx, sy, sz); %! set (h, "color", "r"); %! hold on; %! quiver3 (x, y, z, u, v, w); %! scatter3 (sx(:), sy(:), sz(:), 20, "filled", "o", "markerfacecolor", "r"); %! view (3); %! title ("Spiral Sink"); %! grid on; %! axis equal; %!demo %! clf; %! [x, y, z] = meshgrid (-1:0.4:1, -1:0.4:1, -3:0.3:0); %! a = 0.08; %! b = 0.04; %! u = - a * x - y; %! v = x - a * y; %! w = - b * ones (size (x)); %! hold on; %! sx = 1.0; %! sy = 0.0; %! sz = 0.0; %! plot3 (sx, sy, sz, ".r", "markersize", 15); %! t = linspace (0, 12 * 2 * pi (), 500); %! tx = exp (-a * t).*cos (t); %! ty = exp (-a * t).*sin (t); %! tz = - b * t; %! plot3 (tx, ty, tz, "-b"); %! h = streamline (x, y, z, u, v, w, sx, sy, sz); %! set (h, "color", "r"); %! view (3); %! title ("Heuns Scheme (red) vs. Analytical Solution (blue)"); %! grid on; %! axis equal tight; ## Test input validation %!error <Invalid call> streamline () %!error <Invalid call to streamline> %! hf = figure ("visible", "off"); %! unwind_protect %! hax = axes (); %! streamline (hax); %! unwind_protect_cleanup %! close (hf); %! end_unwind_protect %!error <input data must be 2-D or 3-D> streamline (ones (2,2,2,2))