[CHANGESET] Re: Help with griddata3

[David Bateman]

António Santos wrote:
> Hi,
>
> I have a Fedora Core 6 system with Octave 2.9.9-1 and Octave-forge  
> 2006.07.09-7 installed.
> I need to use the griddata3 function, which seems to not be present in  
> these packages. I tried to download de griddata3.m from other  
> distributions but I'm having no success with using this function.
> griddata3 calls griddata like the following:
> vi = griddata([x(:),y(:),z(:)],v(:),[xi(:),yi(:),zi(:)],varargin{:});
> However, griddata does not accept all these parameters...
> I also downloaded the source code from Octave 3.0.0 and, althought I  
> didn't test it, it seems that the problem still persists.
> Any clue on how to use griddata3?
>
> Thanks,
>
> António Santos
>
>   
Opps, that can't ever have worked as written, but I sure to have tested
this... In any case the fact that it doesn't work is my fault, and the
attached patch should fix it and adds test code.

D.

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# HG changeset patch
# User David Bateman <address@hidden>
# Date 1205330700 -3600
# Node ID 33c8aade7c453c1ae32f46d69298840024e72af6
# Parent  f761dc86ed70deaa223a6c0052c5d8e5a381c6ea
Fix griddata3 and add test code

diff --git a/scripts/ChangeLog b/scripts/ChangeLog
--- a/scripts/ChangeLog
+++ b/scripts/ChangeLog
@@ -1,3 +1,8 @@ 2008-03-11  John W. Eaton  <address@hidden
+2008-03-12  David Bateman  <address@hidden>
+
+       * geometry/griddata3.m: Use griddatan and not griddata
+       internally. Return vi and not yi. Add test code.
+
 2008-03-11  John W. Eaton  <address@hidden>
 
        * plot/__go_draw_axes__.m: Use get to access hidden properties.
diff --git a/scripts/geometry/griddata3.m b/scripts/geometry/griddata3.m
--- a/scripts/geometry/griddata3.m
+++ b/scripts/geometry/griddata3.m
@@ -30,7 +30,7 @@
 
 ## Author: David Bateman <address@hidden>
 
-function [yi] = griddata3 (x, y, z,v, xi, yi, zi, method, varargin)
+function vi = griddata3 (x, y, z, v, xi, yi, zi, method, varargin)
        
   if (nargin < 7)
     print_usage ();
@@ -48,10 +48,33 @@ function [yi] = griddata3 (x, y, z,v, xi
   endif
 
   if (any (size(xi) != size(yi)) || any (size(xi) != size(zi)))
-    error ("griddata: xi, yi and zi must be vectors or matrices of same size");
+    error ("griddata3: xi, yi and zi must be vectors or matrices of same 
size");
   endif
 
-  vi = griddata ([x(:), y(:), z(:)], v(:), [xi(:), yi(:), zi(:)], varargin{:});
+  vi = griddatan ([x(:), y(:), z(:)], v(:), [xi(:), yi(:), zi(:)], 
varargin{:});
   vi = reshape (vi, size (xi));
 endfunction
 
+%!test
+%! 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 = reshape (griddatan([x(:), y(:), z(:)], v, [xi(:), yi(:), zi(:)], 
'linear'), size (xi));
+%! 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)
+
+%!test
+%! 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 = reshape (griddatan([x(:), y(:), z(:)], v, [xi(:), yi(:), zi(:)], 
'linear'), size (xi));
+%! vi = griddata3 (x, y, z, v, xi, yi, zi, 'nearest');
+%! vv = vi - xi.^2 - yi.^2 - zi.^2;
+%! assert (max(abs(vv(:))), 0, 0.1)