Bug 23: Complex "double" inequalities may not shade properly
Symptom: Inequalities which are based on relations that require
evaluation of both positive and negative roots (e.g. hyperbolae like
x^2-y^2 < 6 or absolute values like abs x - abs y > 3) may have
triangular pieces missing from the shaded region.
Cause: The code which computes the region to fill is designed to
work with single-valued functions. To display inequalities such as these,
a number of rather unscientific heuristics are applied to determine how
the regions for the two halves of the relation should be joined. There
appear to be some errors here.
Workaround: In some cases, you can obtain the correct fill behavior
by manipulating the window size slightly. The resulting minor change in the
grid range may cause the boundaries of the region to be computed correctly.
If you notice this bug, please e-mail me the inequality you had trouble with.
(You needn't describe the exact filling defect or send me a screen shot
or anything, unless I cannot reproduce it here.) When I have some time to
dedicate to understanding this bug I will attempt to tweak the code so
that as many of these graphs fill properly as possible.
Status: All cases I have observed are fixed in version 2.0c. If you see any other
inequalities that do not shade properly, please report them to me.