Minus operator versus unary minus

[Dave Farrance]

Peter Otten <__peter__ at web.de> wrote:

>so both +0.0 and -0.0 would be skipped anyway.

Maybe the coder was simply aiming for visibility.  The unary minus can
be hard to spot in some circumstances.  e.g.: I've sneaked a unary minus
into this maths proof, which makes it horrible (although correct):

u and v are vectors (so have an anti-commutative cross-product)
Show that (u - v) x (u + v) = 2u x v

u x (u + v) - v x (u + v)
u x u + u x v - v x u - v x v
u x v - v x u  [ because u x u = 0, v x v = 0]
u x v - (u x -v)
u x v - (-1)(u x v)
u x v + u x v
2(u x v)
2u x v