On Mon, 11 May 2009, Sebastiano Putoto wrote:
 Dear Gretl users,
 
 I know my question may seem (it actually is) very banal, but I can't figure out a way
to check if two matrices are equal.
 
 The point is verifying idempotence and symmetry for an orthogonal projector. The
mathematical proof isn't required here: the point is showing that the actual
calculated
 matrices are orthogonal projectors and therefore have the specified properties; I got to
show the numbers are the same. And apart from arbitrary extraction of submatrices to
 prove they get out same, I can't think of anything 'scientific'.
 
 Hope you will be able to help me with the matter.
 
 Regards,
 
How about
    check = sumc(sumr(abs(mat1-mat2))) < 1.0e-07
or something similar?
Riccardo (Jack) Lucchetti
Dipartimento di Economia
Università Politecnica delle Marche
r.lucchetti(a)univpm.it
http://www.econ.univpm.it/lucchetti