# This function computes the inverse of a square matrix.  Are you
# sure you want to use this?  It's usually much better to use `solve'.

inv = function (M; options)
{
  local (x);

  M = [ M ];
  if (M.nr != M.nc)
  {
    message ("run time error: Matrix must be square to invert.");
    exception ();
  }

  x = solve (M; ident (M.nr); options);

  x.rid = M.cid;
  x.cid = M.rid;

  return x;
};