Re: [Axiom-developer] [Richard Fateman <address@hidden>] Re: [Maxima] strange behaviour with simple decimals / Axiom

[Gabriel Dos Reis]

"Bill Page" <address@hidden> writes:

| Quoting Gabriel Dos Reis <address@hidden>:
| 
| >
| > FYI.
| 
| Here is the result from Maxima:
| 
| Maxima 5.11.99rc1 http://maxima.sourceforge.net
| Using Lisp GNU Common Lisp (GCL) GCL 2.6.8 (aka GCL)
| Distributed under the GNU Public License. See the file
| COPYING. Dedicated to the memory of William Schelter. This is a
| development version of Maxima. The function bug_report()
| provides bug reporting information. (%i1) 1.4^2;
| (%o1)                                1.96
| (%i2) 1.96 - 1.4^2;
| (%o2)                       2.2204460492503131E-16
| (%i3)

I believe that can explained by the fact that Axiom uses the host
"long double" C datatype for DoubleFloat whereas Maxima must be using
the more conventional and reliable "double" C datatype.

| ---------
| 
| Date: Wed, 11 Apr 2007 17:54:35 -0700
| Subject: Re: [Maxima] strange behaviour with simple decimals / Axiom
| From: Richard Fateman <address@hidden>
| To: address@hidden
| In Axiom version of  1/17/2005
| 
| 1.4^2  comes out as 1.96
| 
| 1.96 - 1.4^2  comes out as  0.7 E -20
| 
| I don't know if this counts as unexpected to a 5th grader, but does a
| 5th grader even know about "E" scientific notation?
| 
| ------
| 
| What's his point?

If he reads this mailing list you would get an answer :-)

-- Gaby