[Jprogramming] More on eigenvalues

[John Randall]

While I still suggest using LAPACK for calculating eigenvalues, there
appears to be some interest in an all-J solution.

Here's a (not very elegant) solution using the neglected 128!:0 (QR
reduction).


QR=:128!:0
mp=:+/ . *

f=:mp&>~/ @: QR

g=:3 : 0
z=.f y
while. z~:y do.
y=.z
z=.f y
end.
(<0 1)&|: z
)

A =: 33 16 72 , _24 _10 _57 ,: _8 _4 _17

   g A
3 2 1


Best wishes,

John