[AstroPy] LinearNDInterpolator
Jonathan Slavin
jslavin at cfa.harvard.edu
Fri Apr 22 13:27:51 EDT 2011
Hi all,
I'm wondering if anyone has used the routine
scipy.interpolate.LinearNDInterpolator
>From what I can tell, it should do fast multidimensional linear
interpolations, which is something I could use. My problem is that it
isn't well documented.
What I have is a 3-D grid of data values and what I want is values at a
specific group of non-gridded points. scipy.interpolate.griddata seems
to do the opposite to what I want -- given a set of (non-gridded) points
at which you know the data value, interpolate onto a regular grid. It
seemed like LinearNDInterpolator was what I wanted, but it seems to want
the same input as griddata -- points at which the data value is known.
That is, it takes two inputs points and values where the number of
points must match the no. of values. What I need is something more like
linearinterp(gridded_data, coords) -- that is, more like what
scipy.ndimage.map_coordinates does, but much faster and just linear
(rather than spline) interpolation. I wrote a routine that does this,
and reasonably quickly, but it's pure python and not as fast as I'd
like.
Jon
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