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From: "John D'Errico" <woodchips@rochester.rr.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: interp3
Date: Wed, 8 Apr 2009 03:30:04 +0000 (UTC)
Organization: John D'Errico (1-3LEW5R)
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Ross <fed.rossi@gmail.com> wrote in message <48891dbe-8e0b-410e-9cf4-4dda5e08f94f@v28g2000vbb.googlegroups.com>...
> Hi everyone,
> 
> I am not sure if matlab has a built-in function for this.
> 
> Instead of using interp3 to linearly interpolate a three-dimensional
> function V as follows,
> 
> VI = interp3(X,Y,Z,V,X,Y,ZI),
> 
> I would like to retrieve the value of ZI given that VI,X,Y are known.

When you fix the value of X and Y, this reduces
the problem to a 1-d inverse problem. I would
convert it to a simple problem V(Z) - V0 = 0, for
the given value of V. Now it is just a question of
finding the zero crossings. If you do not know
how to do that, then look for "intersections" on
the file exchange (by Doug Schwarz.)

John