[Gambas-user] Elusive Gambas3 crashing bug

[Benoît Minisini]

> More from GambasTester project....
> 
> 
> A.
> 
> According to documentation these functions are same:
> Debug Ang(-1, 1)
> Debug ATan2(-1, 1)
> 
> 2.35619449019235
> -0.785398163397448
> 
> So, Atan2 seems to make errors.

The documentation is not accurate enough. Ang() and ATan2() are the same 
functions, except that their arguments are inverted!

> 
> 
> B.
> 
> Cos(ACos(0.5)) = 0.5  and Tan(ATan(0.5)) = 0.5 are False!
> Tan(ATan(0.5)) - 0.5 gives 1E-16, so this is seems to be precision problem.
> Is this OK?

Yes. You often have precision problems with floating numbers.

I have the plan to use the "==" operator to implement a floating point 
comparison that would ignore the unsignificant digits, but I must find the 
good algorithm first.

Regards,

-- 
Benoît Minisini