> - line_eq looks too complex in the normal (not containing NANs)
> cases. We should avoid such complexity if possible.
>
> One problem here is that comparison conceals NANness of
> operands. Conversely arithmetics propagate it. We can converge
> NANness into a number. The attached line_eq() doesn that. This
> doesn't have almost no additional complexity when NAN is
> involved. I believe it qbehaves in the same way
> and shares a doubious behavior like this.
>
> =# select '{nan, 1, nan}'::line = '{nan, 2, nan}'::line;
> ?column?
> ----------
> t
>
> But probably no point in fixing(?) it.
I think we should fix it.
> The attached file contains line_eq, point_eq_point and
> circle_same. I expect that line_eq is fast but other two are
> doubious.
I haven't got an attachment.
> . . . Mmm.. The function seems broken. I posted the fix for
> the existing version is posted, and line_perp() in the attched
> file will work fine.
I am incorporating the fix you have posted to the other thread to this patch.