Re: [Gretl-users] Check for idempotent matrix in gretl
On Fri, 13 Apr 2007, Andreas Karlsson wrote:
Could you please add a check for idempotency in matrix? So that
for a matrix, when one chooses Prpoerties > View the output
tells if the matrix is idempotent, just as it now tells if it is
e.g. square, symmetric or positive definite.
Yes. Since we calculate the eigenvalues anyway, I suppose we
could use them to check for idempotence. Can anyone remind me how
that would go (in the general case, allowing for asymmetry)?
Thanks.
Allin.