I think I have a solution for 710677 and a possible solution for
694770.
But before I go further, I'm soliciting comments.
plot2d tries to be smart and checks for smoothness and adaptively
increases the sampling rate if the function is not smooth enough.
Basically if |dy| > |dx| , we add extra sampling points. However, in
the 694770, dy/dx is 100 or more, so we add about 100 times more
samples.
One solution is the check is to compute each dy is relatively
constant, we don't try to extra samples. This should make plotting
fast.
Another solution is to give up trying to be smart. Just plot the
points according to the number of grid points selected, with no
adaptation. If the plot doesn't look right, let the user increase the
grid points or decrease the range.
What do you think about this last alternative? Or should we try to be
smart about plotting?
Ray