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From: rrd@hpfcso.FC.HP.COM (Ray Depew)
Newsgroups: comp.sys.handhelds
Subject: Re: 48 graphing question
Message-ID: <7360083@hpfcso.FC.HP.COM>
Date: 28 Feb 91 21:02:54 GMT
References: <1991Feb27.135704@madden.enet.dec.com>
Organization: Hewlett-Packard, Fort Collins, CO, USA
Lines: 36


 >Here's the question; I have written a short program catered to circuits 
>that speeds up graphing a function, that assumes t as the independent 
>variable, asks for intitial time and final time, and autoscales f(t).
>I would like to be able to enter transient functions without having to enter
>a boolean expression in << >> at the equation prompt. When I tried to do
>this the program kept wanting to evaluate. Is there a way around this, or
>better yet, a method of graphing two functions, one t<0 and the other t>0
>at the same time?
>Thanks, Bill
>--
>Wm P. Madden, Jr.
>North Carolina State University - Raleigh, N.C.
>INTERNET: wpmadden@eos.ncsu.edu	         Ma AT@T: (919) 781-6390
>----------

Hi Bill,

Since you haven't offered much detail, I'm afraid I can't either, but it looks
like the function IFTE is just what you're looking for.  For example, the 
equation

     'IFTE(X>10,0,1)'

will model a step function at x=10.  With some more work, you can use IFTE
to do transient functions.  Bear in mind that IFTE can be nested, that is,

     'IFTE(test1,0,IFTE(test2,10,(IFTE(test3,f1,f2)'

is perfectly valid.


Regards
Ray Depew
HP ICBD -- IC's By Decree
rrd@hpfitst1.hp.com