>? "Expected fails:",INT(10^(_DECIMALS-_ERRORPOWER)/4*_CICLES)
>Could you explain to me how you calculated(which theory) the expected fails, thank you.
Theory of Probability
You have to compute this:
- fixed a random IEEE number X = [0..1)
- and a random error E = [-0.5 .. 0.5)*10^-_ERRORPOWER
- X and E are indipendent
- compute this probability:
p(CARRY(X+X,DECIMALS)=1) Probability (X+X) have a carry at digit _DECIMALS
The probability of fails is
p(CARRY(X+X,_DECIMALS )=1,CARRY((X+E)+(X+E),_DECIMALS )=0)
+
p(CARRY(X+X,_DECIMALS )=0,CARRY((X+E)+(X+E),_DECIMALS )=1)
Compute this for _ERRORPOWER=_DECIMALS,
and you found 1/4.
Then ....
Fabio
Previous
Next
Reply
View the map of this thread
View the map of this thread starting from this message only
View all messages of this thread
View all messages of this thread starting from this message only