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Re: Piecewise functions

• To: mathgroup at smc.vnet.net
• Subject: [mg8921] Re: Piecewise functions
• From: "William F. Campbell" <valentin at wam.umd.edu>
• Date: Sat, 4 Oct 1997 22:08:01 -0400
• Organization: UMD Dept. of Meteorology
• Sender: owner-wri-mathgroup at wolfram.com

Venkateswara Rao Ayyadevara wrote:

> Hi !
>
> I would like to know how to represent piecewise linear functions in
> Mathematica.  I tried searching on-line help but could not find any
> info
> regarding this.
>
> Thanks for your help
>
> Venkat

  I do this all the time, albeit in an inelegant fashion.  Here's an
example:

myabs[x_ /; x<0] := -x
myabs[x_ /; x>=0] := x

This trivially generalizes to more complex functions -- just specify the
valid domain using the /; conditional operator.  However, suppose one
has a spline fit on, say 100 or 1000 subdomains.  How can I avoid typing
100 or 1000 separate function definitions?

--
Bill Campbell                          Correlation is not cause.