Re: Beginner's Question
- To: mathgroup at smc.vnet.net
- Subject: [mg9889] Re: [mg9869] Beginner's Question
- From: seanross at worldnet.att.net
- Date: Sun, 30 Nov 1997 00:39:38 -0500
- References: <199711290510.AAA16892@smc.vnet.net.>
- Sender: owner-wri-mathgroup at wolfram.com
Henri Kowalczyk wrote:
>
> I'm using mathematica to do some matrix manipulation of matrices with
> symbolic elements. I end up with elements having elements that evaluate
> to zero, but instead of zero I get something like
>
> 0.X+0.Y
>
> so my matrices become large with uneeded elements... is there a setting
> I can change so it will automatically evaluate these to zero?
Two ideas: #1)If the elements have any numerical parts to them, then
the "zeroes" might not be zeroes at all, but very small real numbers
that you won't see unless you use FullForm. The thing that makes me
wonder is the presence of the decimal points. You might try using all
integer/rational numbers.
#2) an after the fact transformation might be in order such as
( 0. X+0. Y-Z)/.{0. _->0}
In the above case 0. _ -> 0 means real zero times anything is
transformed to integer zero.
--
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- References:
- Beginner's Question
- From: "Henri Kowalczyk" <hkowalc@eng.clemson.edu>
- Beginner's Question