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From: tim@nijinsky.ipac.caltech.edu (Tim Conrow)
Newsgroups: comp.sys.handhelds
Subject: 48sx ROOT question
Message-ID: <1991Jun24.203727.3043@nntp-server.caltech.edu>
Date: 24 Jun 91 20:37:27 GMT
Sender: news@nntp-server.caltech.edu
Organization: California Institute of Technology
Lines: 39

Hi,
  I KNOW this has been brought up before, but it wasn't of interest then, 
it is now. To avoid boring other csh readers, email will be just fine,
unless you think your reply is of broad interest.
 
  I'd like to use the ROOT function in a program in a way that avoids a 
few problems.

1) Does ROOT always need an algebraic to solve? Does this slow it down?
   I assume programs are faster, n`est pas?
2) Another speed issue: Can ROOT be made to work for less than 12 digit
   precision? Full precision takes too long and is unnecessary for my
   purposes. I tried putting a RND(equation,6) call in my algebraic, but
   it got no faster.
3) This is a small thing, but it bothers me: ROOT requires you to name 
   a  variable to solve for, but I can't make it work naming a local
   variable in a program. Does it always need an global name? This is a
   pain because it means the variable being solved for will be created
   in my current directory, which means I have to do the following
   kludge if all I want is an answer on the stack:
<<  ...   'algrbaic' 'uniqueX' guess ROOT 'unqiueX' PURGE ... >>
   Not horrible, I suppose, but inelegant.

  An ideal solution to all these points would be a mode where a program
is given as the equation, requiring no variable name to solve for, just
using the stack. Like 
<< ... <<program>> guess ROOT ... >>
Does a mode like this exist?
  I know the solver can be used with a program as the equation, but the 
manual is silent on how to do this with ROOT in a program.

  What's the deal? What have I missed? Does the HP Programmer's Manual
deal with this? Are there any publications that do? A pointer to one of
them would be a wonderful response, if you wish to avoid sending a
lengthy explanation.

Thanks all,
-- Tim
tim@ipac.caltech.edu