RPN Program for Eigenvalues?

[Ángel Martin]

Hello Math-heads,

I've been looking for an RPN program that calculates all the Eigenvalues for a generic case, NxN square matrix. Tthat is to say not limited to 3x3, or 4x4, etc.

I'd appreciate your hints if you know of such a program being available somewhere.

BTW, the program below will solve for real eigenvalues, but of course won't find complex values, nor there's a fool-proof method (depends on initial guesses, etc. It is nevertheless an interesting example of the power of the advantage matrix functions, combined with solve.

LBL "*VP"
STO 00
"IDN"
XROM "MIDN"
RCL 00
"X"
MAT*
"IDN,AA,IDN"
MAT-
"IDN"
MDET
RTN
LBL "EIGEN"
"DIM=?"
PROMPT
"AA"
MATDIM
XROM "IMR"
DIM?
"IDN"
MATDIM
E
ENTER^
50
"*VP"
SOLVE
"VP="
ARCL X
AVIEW
END

[Bill Holes]

PPC-TN V1N3 Oct. 1980 may help a bit. A 214 step RPN program to compute all eigenvalues of a real symmetic matrix up to 22 x 22 using Jacobi's method is listed on page 12. I believe it was submitted by Valentin Albillo.

[Ángel Martin]

Bill, right on the money! Thanks so much.