is_detectable

% -*- texinfo -*-
% @deftypefn {Function File} {@var{retval} =} is_detectable (@var{a}, @var{c}, @var{tol}, @var{dflg})
% @deftypefnx {Function File} {@var{retval} =} is_detectable (@var{sys}, @var{tol})
% Test for detectability (observability of unstable modes) of (@var{a}, @var{c}).
%
% Returns 1 if the system @var{a} or the pair (@var{a}, @var{c}) is
% detectable, 0 if not, and -1 if the system has unobservable modes at the
% imaginary axis (unit circle for discrete-time systems).
%
% @strong{See} @command{is_stabilizable} for detailed description of
% arguments and computational method.
% @seealso{is_stabilizable, size, rows, columns, length, ismatrix, isscalar, isvector}
% @end deftypefn