[GAP Forum] Computing eigenvalues with multiplicities

[Moritz Schmitt]

Dear all,

Let's assume we are given an integer matrix like

m := [ [ 1, 0, 0 ], [ 0, -1, 0 ], [ 0, 0, 1 ] ]

How do we compute all eigenvalues of m with multiplicities? If I use the command

Eigenvalues(Rationals, m);

I only get as output

[1,-1]

but actually need something like [1,1,-1]. I browsed GAP's manual but
didn't find anything.

Thanks in advance.

Moritz