2-D dist functions

[Skip Montanaro]

    Brandon> I came up with these two functions that give the same result:
    Brandon> def get_dist1(x1,y1,x2,y2):
    Brandon>     return math.hypot((x2-x1), (y2-y1))

    Brandon> def get_dist2(x1,y1,x2,y2):
    Brandon>     return math.sqrt((x2-x1)**2 + (y2-y1)**2)

    Brandon> However, the thing is that's strange to me is that get_dist1 is
    Brandon> slower than get_dist2.

Look at the man page for hypot.  It appears to do some extra work to avoid
intermediate underflows and overflows.  On my Mac I see this:

     The hypot() and cabs() functions computes the sqrt(x*x+y*y) in such a
     way that underflow will not happen, and overflow occurs only if the
     final result deserves it.

Extra numerical care equates to slower runtime.

Skip