Relativistic addition of velocities in wxMaxima

>>>>> "Robert" == Robert Dodier <robert.dodier at gmail.com> writes:

    Robert> On 2013-09-19, Jon Fleming <jonf at fleming-group.com> wrote:
    >> In wxMaxima I have, after pressing <Ctrl-R>:
    >> 
    >> |  load(vect);
    >> |  u: [-3.84,0,0];
    >> |  v: [0,0,3.84];
    >> |  c: 299792.458;
    >> | CPsquared(v1, v2) := (v1 . v1)*(v2 . v2) - (v1 . v2)^2;
    >> | addrelativistic(v1, v2) := sqrt(((v2 - v1) . (v2 - v1) - CPsquared(v1, v2)/c^2)/(1 - (v2 . v1)^2/c^2)^2);
    >> |      tellsimpafter: circular rule attempted.
    >> |       -- an error. To debug this try: debugmode(true);

    Robert> I gather that ctrl-R tells wxMaxima to reevaluate all cells. One of them
    Robert> is load(vect), but 'vect' defines some simplification rules and if you
    Robert> load it twice, the second time through you get the error about the
    Robert> circular rule. There's certainly no harm in reevaluating the other

We should probably fix it so that load(vect) won't load itself again
if it's already been loaded. Or at least won't redefine simplification
rules.

Unfortunately, I don't know how to do that.

Ray