DISCONTINUITIES IN A CURVE



>>>>> "Rupert" == Rupert Swarbrick <rswarbrick at gmail.com> writes:

    Rupert> Raymond Toy <toy.raymond at gmail.com> writes:
    >> This shouldn't be a problem with the current plot2d.  It uses an
    >> adaptive plotting algorithm to use more points where the curve is
    >> changing too fast.  If, by chance, plot2d tries to evaluate f(1),
    >> maxima catches that error and pretends (I think) that there is a
    >> discontinuity at that point and tries to add more points in the
    >> neighborhood to get a better plot.
    >> 
    >> Of course, if the discontinuity is very narrow and the number of
    >> initial sample points is too sparse, plot2d will never see it and hence
    >> never plot it.  No surprise there.
    >> 
    >> The adaptive plotter isn't used for any other kind of plot such as
    >> parametric plots, unfortunately.

    Rupert> Well, at least on my machine,

    Rupert> f(x) := signum(x) * abs(x)^(-1/n)$
    Rupert> plot2d(f(x), [x, -1, 1.1]), n=10;

    Rupert> displayed the expected behaviour. Maybe I've misunderstood what's going
    Rupert> on.

Ok, I'm not sure what you expect the behavior to be.  With our
example, I see a curve drawn on the y-axis from about y=-2.25 to
y=2.25.  If I change the plot limits to [x, -1,1], I see the same
curve, except there is no line drawn on the y-axis.

Which of these is your expected behavior?  Or were you expecting
something else?

Ray