Mercurial > octave
view scripts/plot/draw/sombrero.m @ 33619:4818ea4e33d9 default tip @
maint: Merge stable to default.
author | Markus Mützel <markus.muetzel@gmx.de> |
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date | Thu, 23 May 2024 16:56:15 +0200 |
parents | 2e484f9f1f18 |
children |
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######################################################################## ## ## Copyright (C) 1993-2024 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 {} {} sombrero () ## @deftypefnx {} {} sombrero (@var{n}) ## @deftypefnx {} {@var{z} =} sombrero (@dots{}) ## @deftypefnx {} {[@var{x}, @var{y}, @var{z}] =} sombrero (@dots{}) ## Plot the familiar 3-D sombrero function. ## ## The function plotted is ## @tex ## $$z = { \rm{sin} (\sqrt {(x^2 + y^2)}) \over \sqrt {(x^2 + y^2)} }$$ ## @end tex ## @ifnottex ## ## @example ## z = sin (sqrt (x^2 + y^2)) / (sqrt (x^2 + y^2)) ## @end example ## ## @end ifnottex ## Called without a return argument, @code{sombrero} plots the surface of the ## above function over the meshgrid [-8,8] using @code{surf}. ## ## If @var{n} is a scalar the plot is made with @var{n} grid lines. ## The default value for @var{n} is 41. ## ## When called with output arguments, return the data for the function ## evaluated over the meshgrid. This can subsequently be plotted with ## @code{surf (@var{x}, @var{y}, @var{z})}. ## ## @seealso{peaks, meshgrid, mesh, surf} ## @end deftypefn function [x, y, z] = sombrero (n = 41) if (n <= 1) error ("sombrero: number of grid lines N must be greater than 1"); endif [xx, yy] = meshgrid (linspace (-8, 8, n)); r = sqrt (xx.^2 + yy.^2) + eps; # eps prevents div/0 errors zz = sin (r) ./ r; if (nargout == 0) surf (xx, yy, zz); elseif (nargout == 1) x = zz; else x = xx; y = yy; z = zz; endif endfunction %!demo %! clf; %! colormap ("default"); %! sombrero (); %! title ("sombrero() function"); ## Test input validation %!error sombrero (1,2,3) %!error <N must be greater than 1> sombrero (1)