Plotting singular functions



>>>>> "Vadim" == Vadim V Zhytnikov <vvzhy@mail.ru> writes:

    Vadim> Raymond Toy ?????:


    Vadim> Is adaptive 3d plotting algorithm available somewhere?

I think yacas has one.  I borrowed the 2D algorithm from yacas.

    Vadim> Other quick and dirty solution is to make "coerce-float-fun"
    Vadim> return 0.0 instead of T for singular points.
    >> The T is needed for the 2D adaptive plotting to work.  A non-number
    >> signals a singularity, so the adaptive plotter can try more points.
    >> 

    Vadim> I see.  But we still can change T->0.0 for 3D plotting as a quick fix.

Yes, this should at least some kind of plot to be done.

    Vadim> I still don't like the fact that 2D plotting wastes time in the hopeless
    Vadim> situation with wrong plotting expression.  I see that the problem can
    Vadim> be resolved by fine-grained error handling but maybe we just can count
    Vadim> number of plot expression evaluations and number of failed evaluations.
    Vadim> If after 10 or 20 attempts these counters equal then plotting must be
    Vadim> aborted.

This sounds like a reasonable approach.  Not likely to have 10 or 20
singularities in a single plot.

Ray