RE: Sorting Eigenvalues/EigenVe
- To: mathgroup at smc.vnet.net
- Subject: [mg8158] RE: [mg8099] Sorting Eigenvalues/EigenVe
- From: Ersek_Ted%PAX1A at mr.nawcad.navy.mil
- Date: Sat, 16 Aug 1997 11:51:02 -0400
- Sender: owner-wri-mathgroup at wolfram.com
Dr. Slater wrote:
|Is there an easy way to sort the results of EigenSystem so that the
|eigenvalues are in increasing order? I can pull them out of the results and
|sort them, but the association of the eigenvalues with the eigenvectors is
|lost.
The code below should help.
It's a version of routine by Wouter
(see [mg6402] from Mar 97)
In[1]:= ColumnSort[m_?MatrixQ, colm_Integer/;
( colm<=Dimensions[m][[2]] )]:=
Sort[m, OrderedQ[{#1[[colm]] ,#2[[colm]] }]&]
In[2]:= m=Table[Random[Integer, 25], {8}, {3}];
MatrixForm[m]
Out[2]= (*** A Random Matrix of Integers ***)
In[3]:= ColumnSort[m, 1]//MatrixForm
Out[3]= (****** The Matrix above after sorting the rows according
to the element in the first column. ********)
Ted Ersek