Re: Question: how does mathematica determine the coefficient of the
- To: mathgroup at smc.vnet.net
- Subject: [mg85007] Re: Question: how does mathematica determine the coefficient of the
- From: "gogoant06 at yahoo.com.hk" <gogoant06 at yahoo.com.hk>
- Date: Tue, 22 Jan 2008 05:38:30 -0500 (EST)
- References: <fmng23$377$1@smc.vnet.net> <fmq068$anh$1@smc.vnet.net>
On 1=D4=C218=C8=D5, =CF=C2=CE=E76=CA=B148=B7=D6, Jens-Peer Kuska <ku...@info=
rmatik.uni-leipzig.de>
wrote:
> Hi,
>
> because if v is an eigenvector also a*v with
> any scalar value a is an eigenvector and this mean
> you can use what you like and Mathematica don't like
> -1, it likes 1 ..
>
> Regards
> Jens
>
>
>
> gogoan... at yahoo.com.hk wrote:
> > For an example:
>
> > Input:
> > test = {{1, 2}, {2, 1}};
> > Eigensystem[test]
>
> > Output:
> > {{3, -1}, {{1, 1}, {-1, 1}}}
>
> > Why aren't the eigenvectors be {-1,-1}, {1,-1}...?
> > Is there some rule for mathematica to choose out the eigenvectors?- =D2=
=FE=B2=D8=B1=BB=D2=FD=D3=C3=CE=C4=D7=D6 -
>
> - =CF=D4=CA=BE=D2=FD=D3=C3=B5=C4=CE=C4=D7=D6 -
I've found out that for matrix with nonexact numbers, the largest
absolute value is always a positive real number.
I know that both are eigenvectors, but i would like to find out how
mathematica choose them because i am dealing with a smoothly changing
matrix...
Thanks anyway.