######################################################################## ## ## Copyright (C) 2007-2020 The Octave Project Developers ## ## See the file COPYRIGHT.md in the top-level directory of this ## distribution or . ## ## 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 ## . ## ######################################################################## ## -*- texinfo -*- ## @deftypefn {} {@var{vi} =} griddata3 (@var{x}, @var{y}, @var{z}, @var{v}, @var{xi}, @var{yi}, @var{zi}) ## @deftypefnx {} {@var{vi} =} griddata3 (@var{x}, @var{y}, @var{z}, @var{v}, @var{xi}, @var{yi}, @var{zi}, @var{method}) ## @deftypefnx {} {@var{vi} =} griddata3 (@var{x}, @var{y}, @var{z}, @var{v}, @var{xi}, @var{yi}, @var{zi}, @var{method}, @var{options}) ## ## Generate a regular mesh from irregular data using interpolation. ## ## The function is defined by @code{@var{v} = f (@var{x}, @var{y}, @var{z})}. ## The interpolation points are specified by @var{xi}, @var{yi}, @var{zi}. ## ## 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, griddatan, delaunayn} ## @end deftypefn function vi = griddata3 (x, y, z, v, xi, yi, zi, method = 'linear', varargin) if (nargin < 7) print_usage (); endif if (isvector (x) && isvector (y) && isvector (z) && isvector (v)) if (! isequal (length (x), length (y), length (z), length (v))) error ("griddata: X, Y, Z, and V must be vectors of the same length"); endif elseif (! size_equal (x, y, z, v)) error ("griddata: X, Y, Z, and V must have equal sizes"); endif ## meshgrid xi, yi and zi if they are vectors unless ## they are vectors of the same length. if (isvector (xi) && isvector (yi) && isvector (zi)) if (! isequal (length (xi), length (yi), length (zi))) [xi, yi, zi] = meshgrid (xi, yi, zi); else ## Otherwise, convert to column vectors xi = xi(:); yi = yi(:); zi = zi(:); endif endif if (! size_equal (xi, yi, zi)) error ("griddata3: XI, YI, and ZI must be vectors or matrices of the same size"); endif vi = griddatan ([x(:), y(:), z(:)], v(:), [xi(:), yi(:), zi(:)], method, varargin{:}); vi = reshape (vi, size (xi)); endfunction %!testif HAVE_QHULL %! old_state = rand ("state"); %! restore_state = onCleanup (@() rand ("state", old_state)); %! rand ("state", 0); %! x = 2 * rand (1000, 1) - 1; %! y = 2 * rand (1000, 1) - 1; %! z = 2 * rand (1000, 1) - 1; %! v = x.^2 + y.^2 + z.^2; %! [xi, yi, zi] = meshgrid (-0.8:0.2:0.8); %! vi = griddata3 (x, y, z, v, xi, yi, zi, "linear"); %! vv = vi - xi.^2 - yi.^2 - zi.^2; %! assert (max (abs (vv(:))), 0, 0.1); %!testif HAVE_QHULL %! old_state = rand ("state"); %! restore_state = onCleanup (@() rand ("state", old_state)); %! rand ("state", 0); %! x = 2 * rand (1000, 1) - 1; %! y = 2 * rand (1000, 1) - 1; %! z = 2 * rand (1000, 1) - 1; %! v = x.^2 + y.^2 + z.^2; %! [xi, yi, zi] = meshgrid (-0.8:0.2:0.8); %! vi = griddata3 (x, y, z, v, xi, yi, zi, "nearest"); %! vv = vi - xi.^2 - yi.^2 - zi.^2; %! assert (max (abs (vv(:))), 0.385, 0.1);