Mercurial > octave
view scripts/geometry/griddata3.m @ 31197:8d4c87e88d0e
maint: Merge stable to default.
author | Markus Mützel <markus.muetzel@gmx.de> |
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date | Tue, 23 Aug 2022 19:45:19 +0200 |
parents | 796f54d4ddbf |
children | 597f3ee61a48 |
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######################################################################## ## ## Copyright (C) 2007-2022 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 {} {@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}) ## ## Interpolate irregular 3-D source data at specified points. ## ## The inputs @var{x}, @var{y}, and @var{z} define the points where the ## function @code{@var{v} = f (@var{x}, @var{y}, @var{z})} is evaluated. The ## inputs @var{x}, @var{y}, @var{z} are either vectors of the same length, or ## if they are of unequal length, then they are expanded to a 3-D grid with ## @code{meshgrid}. The size of the input @var{v} must match the size of the ## original data, either as a vector or a matrix. ## ## The interpolation points are specified by @var{xi}, @var{yi}, @var{zi}. ## ## The optional input interpolation @var{method} can be @qcode{"nearest"} or ## @qcode{"linear"}. When the method is @qcode{"nearest"}, the output @var{vi} ## will be the closest point in the original data (@var{x}, @var{y}, @var{z}) ## to the query point (@var{xi}, @var{yi}, @var{zi}). When the method is ## @qcode{"linear"}, the output @var{vi} will be a linear interpolation between ## the two closest points in the original source data in each dimension. ## If @var{method} is omitted or empty, 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. ## ## Programming Notes: If the input is complex the real and imaginary parts ## are interpolated separately. Interpolation is based on a Delaunay ## triangulation and any query values outside the convex hull of the input ## points will return @code{NaN}. ## @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); ## FIXME: Ideally, there should be BIST tests for input validation. ## However, this function is deprecated in Matlab and it probably isn't worth ## the coding time to work on a function that will be removed soon.