% -*- texinfo -*-
% @deftypefn {Function File} {} obsv (@var{sys}, @var{c})
% @deftypefnx {Function File} {} obsv (@var{a}, @var{c})
% Build observability matrix:
% @iftex
% @tex
% $$ Q_b = \left[ \matrix{ C \cr
% CA \cr
% CA^2 \cr
% \vdots \cr
% CA^{n-1} } \right ] $$
% @end tex
% @end iftex
% @ifinfo
% @example
% @group
% | C |
% | CA |
% Qb = | CA^2 |
% | ... |
% | CA^(n-1) |
% @end group
% @end example
% @end ifinfo
% of a system data structure or the pair (@var{a}, @var{c}).
%
% The numerical properties of @command{is_observable}
% are much better for observability tests.
% @end deftypefn