-0.0 versus 0.0

[Dave Sworin]

Sometimes a variable, after lots of calculations, is instantiated to a

float value of -0.0 in the gprolog interpreter.  When I compare the

variable to 0.0, as in X =:= 0.0, it succeeds.  X < 0.0 fails.  What

is the significance of the minus sign?  Is the return of -0.0 intentional?

I don't have a simple example as this usually occurs after some

matrix operations with lots of additions and multiplications.

 

Dave