Mercurial > octave
view scripts/geometry/griddatan.m @ 27919:1891570abac8
update Octave Project Developers copyright for the new year
In files that have the "Octave Project Developers" copyright notice,
update for 2020.
author | John W. Eaton <jwe@octave.org> |
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date | Mon, 06 Jan 2020 22:29:51 -0500 |
parents | b442ec6dda5c |
children | bd51beb6205e |
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## Copyright (C) 2007-2020 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this distribution ## or <https://octave.org/COPYRIGHT.html/>. ## ## ## 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 {} {@var{yi} =} griddatan (@var{x}, @var{y}, @var{xi}) ## @deftypefnx {} {@var{yi} =} griddatan (@var{x}, @var{y}, @var{xi}, @var{method}) ## @deftypefnx {} {@var{yi} =} griddatan (@var{x}, @var{y}, @var{xi}, @var{method}, @var{options}) ## ## Generate a regular mesh from irregular data using interpolation. ## ## The function is defined by @code{@var{y} = f (@var{x})}. ## The interpolation points are all @var{xi}. ## ## The interpolation method can be @qcode{"nearest"} or @qcode{"linear"}. ## If method is omitted it defaults to @qcode{"linear"}. ## ## The optional argument @var{options} is passed directly to Qhull when ## computing the Delaunay triangulation used for interpolation. See ## @code{delaunayn} for information on the defaults and how to pass different ## values. ## @seealso{griddata, griddata3, delaunayn} ## @end deftypefn ## Author: David Bateman <dbateman@free.fr> function yi = griddatan (x, y, xi, method = "linear", varargin) if (nargin < 3) print_usage (); endif if (ischar (method)) method = tolower (method); endif [m, n] = size (x); [mi, ni] = size (xi); if (n != ni || rows (y) != m || columns (y) != 1) error ("griddatan: dimensional mismatch"); endif ## Bug #50494 (loss of precision unless non-default Qhull options used) if (isempty (varargin) && n <= 3) varargin{1} = {"Qt", "Qbb", "Qc"}; endif ## triangulate data tri = delaunayn (x, varargin{:}); yi = NaN (mi, 1); if (strcmp (method, "nearest")) ## search index of nearest point idx = dsearchn (x, tri, xi); valid = ! isnan (idx); yi(valid) = y(idx(valid)); elseif (strcmp (method, "linear")) ## search for every point the enclosing triangle [tri_list, bary_list] = tsearchn (x, tri, xi); ## only keep the points within triangles. valid = ! isnan (tri_list); tri_list = tri_list(valid); bary_list = bary_list(valid, :); nr_t = rows (tri_list); ## Use barycentric coordinate of point to calculate yi if (isscalar (tri_list)) ## Special case required by orientation rules for vector/vector index. yi(valid) = sum (y(tri(tri_list,:)).' .* bary_list, 2); else yi(valid) = sum (y(tri(tri_list,:)) .* bary_list, 2); endif else error ("griddatan: unknown interpolation METHOD"); endif endfunction %!testif HAVE_QHULL %! [xx,yy] = meshgrid (linspace (-1,1,32)); %! xi = [xx(:), yy(:)]; %! x = 2*rand (100,2) - 1; %! x = [x;1,1;1,-1;-1,-1;-1,1]; %! y = sin (2 * sum (x.^2,2)); %! zz = griddatan (x,y,xi,"linear"); %! zz2 = griddata (x(:,1),x(:,2),y,xi(:,1),xi(:,2),"linear"); %! assert (zz, zz2, 1e-10); %!testif HAVE_QHULL %! [xx,yy] = meshgrid (linspace (-1,1,32)); %! xi = [xx(:), yy(:)]; %! x = 2*rand (100,2) - 1; %! x = [x;1,1;1,-1;-1,-1;-1,1]; %! y = sin (2*sum (x.^2,2)); %! zz = griddatan (x,y,xi,"nearest"); %! zz2 = griddata (x(:,1),x(:,2),y,xi(:,1),xi(:,2),"nearest"); %! assert (zz, zz2, 1e-10); %!testif HAVE_QHULL <56515> %! x = [ 0, 0; 1, 1; 0, 1; 1, 0 ]; %! y = [ 1; 2; 3; 4 ]; %! xi = [ .5, .5 ]; %! yi = griddatan (x, y, xi);