Re: Interpolation with vectors
- To: mathgroup at smc.vnet.net
- Subject: [mg84699] Re: Interpolation with vectors
- From: nigol <dario.buttari at gmail.com>
- Date: Thu, 10 Jan 2008 02:28:50 -0500 (EST)
- References: <flvnjk$7ck$1@smc.vnet.net>
Daniel,
I think the documentation is wrong or the function implementation is wrong.
In mathematica 6.0.1 the correct syntax for your example seems to be:
In[1]:= Interpolation[{{1, {{1, 1}}}, {2, {{1, 2}}}},
InterpolationOrder -> 1][1.5]
Out[1]= {1, 1.5}
Your original syntax is interpreted as equivalent to:
In[3]:= Interpolation[{{{1}, 1, 1}, {{2}, 1, 2}},
InterpolationOrder -> 1][1.5]
Out[3]= 0.875
In that syntax the two numbers following the x location specify f1 and
df1 (derivative of the function at the interpolation point).
You can plot:
Plot[Interpolation[{{1, {1, 1}}, {2, {1, 2}}},
InterpolationOrder -> 1][x], {x, 1, 2}]
to understand what is going on.
Dario