Function: alghassei
Section: algebras
C-Name: alghassei
Prototype: mG
Help: alghassei(al): the hasse invariant of the central simple algebra al
 at infinite places.
Doc: Given a central simple algebra \var{al} output by \tet{alginit}, returns
 a \typ{VECSMALL} $h_i$ of $r_1$ integers modulo the degree $d$ of \var{al},
 where $r_1$ is the number of real places of the center: the local Hasse
 invariants of \var{al} at infinite places.
 \bprog
 ? nf = nfinit(y^2-5);
 ? A = alginit(nf, [-1,y]);
 ? alghassei(A)
 %3 = Vecsmall([1, 0])
 @eprog
