% -*- texinfo -*-
% @deftypefn {Function File} {} null (@var{a}, @var{tol})
% Return an orthonormal basis of the null space of @var{a}.
%
% The dimension of the null space is taken as the number of singular
% values of @var{a} not greater than @var{tol}. If the argument @var{tol}
% is missing, it is computed as
%
% @example
% max (size (@var{a})) * max (svd (@var{a})) * eps
% @end example
% @end deftypefn