Mercurial > octave-nkf
annotate scripts/general/interp1q.m @ 9051:1bf0ce0930be
Grammar check TexInfo in all .m files
Cleanup documentation sources to follow a few consistent rules.
Spellcheck was NOT done. (but will be in another changeset)
| author | Rik <rdrider0-list@yahoo.com> |
|---|---|
| date | Fri, 27 Mar 2009 22:31:03 -0700 |
| parents | a41df65f3f00 |
| children | 16f53d29049f |
| rev | line source |
|---|---|
| 7785 | 1 ## Copyright (C) 2008 David Bateman |
| 2 ## | |
| 3 ## This file is part of Octave. | |
| 4 ## | |
| 5 ## Octave is free software; you can redistribute it and/or modify it | |
| 6 ## under the terms of the GNU General Public License as published by | |
| 7 ## the Free Software Foundation; either version 3 of the License, or (at | |
| 8 ## your option) any later version. | |
| 9 ## | |
| 10 ## Octave is distributed in the hope that it will be useful, but | |
| 11 ## WITHOUT ANY WARRANTY; without even the implied warranty of | |
| 12 ## MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
| 13 ## General Public License for more details. | |
| 14 ## | |
| 15 ## You should have received a copy of the GNU General Public License | |
| 16 ## along with Octave; see the file COPYING. If not, see | |
| 17 ## <http://www.gnu.org/licenses/>. | |
| 18 | |
| 19 ## -*- texinfo -*- | |
| 20 ## @deftypefn {Function File} {@var{yi} =} interp1q (@var{x}, @var{y}, @var{xi}) | |
| 21 ## One-dimensional linear interpolation without error checking. | |
| 22 ## Interpolates @var{y}, defined at the points @var{x}, at the points | |
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9051
1bf0ce0930be
Grammar check TexInfo in all .m files
Rik <rdrider0-list@yahoo.com>
parents:
7815
diff
changeset
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23 ## @var{xi}. The sample points @var{x} must be a strictly monotonically |
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1bf0ce0930be
Grammar check TexInfo in all .m files
Rik <rdrider0-list@yahoo.com>
parents:
7815
diff
changeset
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24 ## increasing column vector. If @var{y} is an array, treat the columns |
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1bf0ce0930be
Grammar check TexInfo in all .m files
Rik <rdrider0-list@yahoo.com>
parents:
7815
diff
changeset
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25 ## of @var{y} separately. If @var{y} is a vector, it must be a column |
| 7785 | 26 ## vector of the same length as @var{x}. |
| 27 ## | |
| 28 ## Values of @var{xi} beyond the endpoints of the interpolation result | |
| 29 ## in NA being returned. | |
| 30 ## | |
| 31 ## Note that the error checking is only a significant portion of the | |
| 32 ## execution time of this @code{interp1} if the size of the input arguments | |
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9051
1bf0ce0930be
Grammar check TexInfo in all .m files
Rik <rdrider0-list@yahoo.com>
parents:
7815
diff
changeset
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33 ## is relatively small. Therefore, the benefit of using @code{interp1q} |
| 7785 | 34 ## is relatively small. |
| 35 ## @seealso{interp1} | |
| 36 ## @end deftypefn | |
| 37 | |
| 38 function yi = interp1q (x, y, xi) | |
| 39 x = x(:); | |
| 40 nx = size (x, 1); | |
| 41 szy = size (y); | |
| 42 ny = szy (1); | |
| 43 nc = prod (szy (2 : end)); | |
| 44 y = reshape (y, ny, nc); | |
| 45 szx = size (xi); | |
| 46 xi = xi (:); | |
| 47 range = find (xi >= x (1) & xi <= x (nx)); | |
| 48 yi = NA (size(xi, 1), size (y, 2)); | |
| 49 xi = xi (range); | |
| 50 dy = y (2 : ny, :) - y (1 : ny - 1, :); | |
| 51 dx = x (2 : nx) - x (1 : nx - 1); | |
| 52 idx = lookup (x, xi, "lr"); | |
| 53 s = (xi - x (idx)) ./ dx (idx); | |
| 54 yi (range, :) = s (:, ones (1, nc)) .* dy (idx, :) + y (idx, :); | |
| 55 if (length (szx) == 2 && any (szx == 1)) | |
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56 yi = reshape (yi, [max(szx), szy(2:end)]); |
| 7785 | 57 else |
| 58 yi = reshape (yi, [szx, szy(2:end)]); | |
| 59 endif | |
| 60 endfunction | |
| 61 | |
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62 %!shared xp, yp, xi, yi |
| 7785 | 63 %! xp=[0:2:10].'; yp = sin(2*pi*xp/5); |
| 64 %! xi = [-1; 0; 2.2; 4; 6.6; 10; 11]; | |
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65 %! yi = interp1 (xp,yp,xi); |
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66 %!assert (interp1q(xp, yp, [min(xp)-1; max(xp)+1]), [NA; NA]); |
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67 %!assert (interp1q(xp,yp,xp), yp, 100*eps); |
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68 %!assert (isempty(interp1q(xp,yp,[]))); |
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a41df65f3f00
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David Bateman <dbateman@free.fr>
parents:
7785
diff
changeset
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69 %!assert (interp1q(xp,yp,xi), yi); |
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a41df65f3f00
Add some single precision test code and fix resulting bugs
David Bateman <dbateman@free.fr>
parents:
7785
diff
changeset
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70 %!assert (interp1q(xp,[yp,yp],xi), [yi, yi]); |
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a41df65f3f00
Add some single precision test code and fix resulting bugs
David Bateman <dbateman@free.fr>
parents:
7785
diff
changeset
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71 %!assert (interp1q(xp,yp,[xi,xi]), [yi, yi]); |
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a41df65f3f00
Add some single precision test code and fix resulting bugs
David Bateman <dbateman@free.fr>
parents:
7785
diff
changeset
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72 %!assert (interp1q(xp,[yp,yp],[xi,xi]), cat (3, [yi, yi], [yi, yi])); |