Fabio,
>
>if fn() is deterministic and v1=v2 then fn(v1)=fn(v2)
>
You are under the mis-assumption here that v1 is exactly equal to v2. In the code you are posting, that is not true.
>VFP language is a not deterministic language.
Yes, it is.
Floating point numbers on binary computers are not deterministic, and there is no computer language that can compensate for this.