Q: Union and precision.

• To: mathgroup at smc.vnet.net
• Subject: [mg8529] Q: Union and precision.
• From: Gadi Oron <oron at manet.pmmh.espci.fr>
• Date: Thu, 4 Sep 1997 02:20:33 -0400
• Organization: Acces regional Ile-de-France (Univ. Paris VI/VII) - France
• Sender: owner-wri-mathgroup at wolfram.com

```Hello again,

How can I force Union to consider numbers equal in the current
precision as equal? Explanation:

In:= 	a=SetPrecision[1.234567,2]
Out:= 	1.2

In:= 	b=SetPrecision[1.234561,2]  (* Notice difference *)
Out:= 	1.2

In:= 	a==b
Out:=	True

In:=	Union[{a,b}]
Out:=	{1.2,1.2} (* !!! *)

How does Union evaluates equalities? How can I force it to do it the right
way??

Thanx.
| EMAIL :  oron at pmmh.espci.fr   ::::     oron at clipper.ens.fr  |
| Homepage : http://pmmh.espci.fr/~oron/personal.html         |
| fido : 2:325/302.8                                          |
| 		  Soyez braves - be brave.                    |
/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/\/

```

• Prev by Date: Re: lists of pairs
• Next by Date: Re: Hyperlinks in Mathematica 3.0 notebooks.
• Previous by thread: Q??: Solve::"eqf": "False is not a well-formed equation
• Next by thread: RE: Q: Union and precision.