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1 ## Copyright (C) 2007 David Bateman |
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2 ## |
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3 ## This file is part of Octave. |
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4 ## |
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5 ## Octave is free software; you can redistribute it and/or modify it |
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6 ## under the terms of the GNU General Public License as published by |
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7 ## the Free Software Foundation; either version 3 of the License, or (at |
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8 ## your option) any later version. |
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9 ## |
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10 ## Octave is distributed in the hope that it will be useful, but |
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11 ## WITHOUT ANY WARRANTY; without even the implied warranty of |
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12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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13 ## General Public License for more details. |
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14 ## |
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15 ## You should have received a copy of the GNU General Public License |
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16 ## along with Octave; see the file COPYING. If not, see |
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17 ## <http://www.gnu.org/licenses/>. |
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18 |
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19 ## Undocumented internal function. |
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20 |
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21 ## -*- texinfo -*- |
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22 ## @deftypefn {Function File} {@var{yi} =} __splinen__ (@var{x}, @var{y}, @var{xi}) |
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23 ## Internal support function for multi-dimensional splines. |
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24 ## @end deftypefn |
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25 |
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26 ## FIXME: Allow arbitrary grids.. |
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27 |
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28 function yi = __splinen__ (x, y, xi, extrapval, f) |
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29 if (nargin != 5) |
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30 error ("Incorrect number of arguments"); |
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31 endif |
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32 ## ND isvector function. |
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33 isvec = @(x) numel (x) == length (x); |
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34 if (!iscell (x) || length(x) < ndims(y) || any (! cellfun (isvec, x)) || |
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35 !iscell (xi) || length(xi) < ndims(y) || any (! cellfun (isvec, xi))) |
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36 error ("%s: non gridded data or dimensions inconsistent", f); |
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37 endif |
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38 yi = y; |
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39 for i = length(x):-1:1 |
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40 yi = permute (spline (x{i}, yi, xi{i}), [length(x),1:length(x)-1]); |
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41 endfor |
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42 |
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43 [xi{:}] = ndgrid (cellfun (@(x) x(:), xi, "UniformOutput", false){:}); |
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44 idx = zeros (size(xi{1})); |
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45 for i = 1 : length(x) |
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46 idx |= xi{i} < min (x{i}(:)) | xi{i} > max (x{i}(:)); |
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47 endfor |
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48 yi(idx) = extrapval; |
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49 endfunction |
