       Re: Piecewise functions

• To: mathgroup at smc.vnet.net
• Subject: [mg8906] Re: Piecewise functions
• From: "Stephen P Luttrell" <luttrell at signal.dra.hmg.gb>
• Date: Thu, 2 Oct 1997 22:56:58 -0400
• Organization: Defence Evaluation and Research Agency
• Sender: owner-wri-mathgroup at wolfram.com

```Venkateswara Rao Ayyadevara <va2a+ at andrew.cmu.edu> wrote in article
<60s2hp\$6mj at smc.vnet.net>...
> 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.

Here is an example notebook showing two different ways of defining a
piecewise linear function (Mathematica 3):

Notebook[{
Cell["Piecewise linear function using Calculus`DiracDelta`:", "Text"],

Cell[BoxData[
\(<< Calculus`DiracDelta`\)], "Input"],

Cell[BoxData[
\(f[x_] := \(-x\)\ UnitStep[\(-x\)] + x\ UnitStep[x]\)], "Input"],

Cell[BoxData[
\(\(Plot[f[x], {x, \(-1\), 1}]; \)\)], "Input"],

Cell["Alternatively you can do it this way:", "Text"],

Cell[BoxData[{
\(g[x_] := \(-x\) /; x \[LessEqual] 0\),
\(g[x_] := x /; x \[GreaterEqual] 0\)}], "Input"],

Cell[BoxData[
\(\(Plot[g[x], {x, \(-1\), 1}]; \)\)], "Input"]
},
FrontEndVersion->"Microsoft Windows 3.0",
ScreenRectangle->{{0, 1024}, {0, 712}},
WindowSize->{496, 604},
WindowMargins->{{0, Automatic}, {Automatic, 0}}
]

--
Stephen P Luttrell
luttrell at signal.dra.hmg.gb