Bug in Interpolation for multi-d data?
- To: mathgroup at smc.vnet.net
- Subject: [mg85979] Bug in Interpolation for multi-d data?
- From: oshaughn <oshaughn at northwestern.edu>
- Date: Fri, 29 Feb 2008 06:24:30 -0500 (EST)
Hello,
Interpolation on multi-d data gives different answers depending on the
order in which the elements are *ordered* in the list. As far as I
can tell, this is not documented.
The sorted element order seems to produce the right results.
Example 1:
dat = Flatten[
Table[{{x, y}, Sin[x] Sin[2 y]}, {x, -3, 3, 0.1}, {y, -3, 3, 0.1}],
1];
dat[[{1, 2, 3}]]
intp = Interpolation[dat];
ListPlot3D[Flatten /@ dat]
Plot3D[intp[x, y], {x, -3, 3}, {y, -3, 3}]
Example 2:
dat = Flatten[
Table[{{x, y}, Sin[x] Sin[2 y]}, {y, -3, 3, 0.1}, {x, -3, 3, 0.1}],
1];
dat[[{1, 2, 3}]]
intp = Interpolation[dat];
ListPlot3D[Flatten /@ dat]
Plot3D[intp[x, y], {x, -3, 3}, {y, -3, 3}]
Example 3:
dat = Flatten[
Table[{{x, y}, Sin[x] Sin[2 y]}, {y, -3, 3, 0.1}, {x, -3, 3, 0.1}],
1]//Sort;
dat[[{1, 2, 3}]]
intp = Interpolation[dat];
ListPlot3D[Flatten /@ dat]
Plot3D[intp[x, y], {x, -3, 3}, {y, -3, 3}]
Am I missing something obvious in the documentation?