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From: pgh@stl.stc.co.uk (Peter Hamer)
Newsgroups: comp.lang.fortran
Subject: Re: splines
Message-ID: <578@acer.stl.stc.co.uk>
Date: Sun, 13-Sep-87 12:00:36 EDT
Article-I.D.: acer.578
Posted: Sun Sep 13 12:00:36 1987
Date-Received: Tue, 15-Sep-87 01:50:52 EDT
References: <442@hubcap.UUCP>
Reply-To: pgh@stl.UUCP (Peter Hamer)
Organization: STL,Harlow,UK.
Lines: 36
Keywords: 2-d

In article <442@hubcap.UUCP> yorkall@hubcap.UUCP (Allen R York) writes:
>Does anyone have a clues as to where I may get a 2-D spline
>interpolation subroutine.  I have found plenty of 1-D routines
>but the 2-D seems to be a different matter.
>
>I want to use this in my research and don't want and probably couldn't
>write my own routine.  
>
>thanks in advance
>
>Allen York
>
>UUCP: {al}!gatech!hubcap!yorkall
>INTERNET: {al}@hubcap.clemson.edu
>
>:write
A simple algorithm for 2-D interpolation is given in "Numerical
Recipes", Press et al, CUP.  This explains the technique and provides
code in FORTRAN and Pascal.  It also assumes you know the value of the
function on a fixed grid.

This book is a good source of numerical techniques, and I recommend
it.

However, *why* do you want to interpolate? Is it as a first step in
some more complicated process (eg plotting contour lines), do you
really want to smooth rather than interpolate between accurately known
points, do you know the points on a fixed grid, why cannot you just
calculate the function, do you need continuity of derivatives?

In other words, if can you explain your problem more fully we may be
able to provide more help.
-- 

Regards,
	  Peter Hamer  (pgh@stl   ...!mcvax!ukc!stl!pgh    +44-279-29531 x 3192)