qmult

% -*- texinfo -*-
% @deftypefn {Function File} {} qmult (@var{a}, @var{b})
% Multiply two quaternions.
%
% @example
% [w, x, y, z] = w*i + x*j + y*k + z
% @end example
%
% @noindent
% identities:
%
% @example
% i^2 = j^2 = k^2 = -1
% ij = k                 jk = i
% ki = j                 kj = -i
% ji = -k                ik = -j
% @end example
% @end deftypefn