Re: Interval[{a,b}]-Interval[{a,b}] = 0?
- To: mathgroup at smc.vnet.net
- Subject: [mg66629] Re: Interval[{a,b}]-Interval[{a,b}] = 0?
- From: Johan Grönqvist <johan.gronqvist at gmail.com>
- Date: Wed, 24 May 2006 04:10:16 -0400 (EDT)
- Organization: Lund University, Sweden
- References: <e510r2$8eg$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Richard Fateman wrote:
> Is this a bug or a feature?
> Notice that Interval[{-1,1}]-Interval[{-1,1}] is Interval[{-2,2}].
Interval arithmetic with a hopefully understandable notation:
You start with [-1,1] and subtract from that [-1,1]
This means:
Result = { x-y | x and y are in [-1,1] }
Then the Result will be A = [-2,2], and this is what you get.
Try also [-1,1] * [-1,1] to see that you get a result obtained in the
same way.
This is good for calculating with numbers having errors, among (probably)
other things.
say [x-error,x+error] - [y-error,y+error] and you get the result x-y
with the error in the form [x-y - 2error, x-y + 2error]
Good for handling experimental data.
/ johan
>
> (I'm using Mathematica 5.1)
>
> RJF
>