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 ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
