Sorted eigenvectors

Robert Israel — Fri, 05 Feb 2010 22:36:44 Z

If your Matrix has shape=symmetric and float entries, I believe the eigenvalues will in fact be sorted in increasing order. But let's say you have a non-symmetric matrix. The eigenvalues may be complex, but I'll sort them in order of decreasing absolute value. You could use sorting with attributes, which (by coincidence?) Joe Riel just posted about:

> E, V:= Eigenvectors(M);
  P := map(attributes, sort([seq(setattribute(evalf(abs(E[i])),i), i = rtable_dims(E))],`>`));
  SortedEs:= [seq(E[p],p=P)];
  SortedVs:= [seq(Column(V,p),p=P)];

Ahh, thanks Robert! Without

mjmoore — Fri, 05 Feb 2010 23:40:56 Z

Ahh, thanks Robert! Without the abs (I'm working with real eigenvalues) it works just fine!

Cheers,
Mike

MaplePrimes - answers and comments on Question, Eigenvector ordering

Sorted eigenvectors

Ahh, thanks Robert! Without