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> > > Hello Pierre Orphelin,
> > >
> > > Let's imagine for a moment that no such terrible things as
> > > "errors over bars", "double precision" and "epsilon" are exist.
> > > To do this let's look at the simple Indicator with Single
> > > precision, Single bar (lastbaronchart) and hopefully no "epsilon"
> > > (whatever it is):
> > >
> > > {########################################}
> > > If LastBarOnChart Then Begin
> > > Value1 = 10.3 - 10.2;
> > > Value2 = 10.2 - 10.1;
> > > If Value1 > Value2 Then Value3 = 1 Else Value3=0;
> > > plot1 (Value3);
> > > End;
> > > {########################################}
> > >
Here is an other misunderstanding of Float 7 digits precision
If LastBarOnChart Then Begin
Value1 = 10.3 - 10.2;
Value2 = 10.2 - 10.1;
If Value1 > Value2 Then Value3 = 1 Else Value3=0;
plot1 (Value3);
messagelog(value1:15:15,value2:15:15);
End;
Produces:
0.100000000000000 // 0.099999400000000 //
Precision is impossible to determine // Precison is obviously 5
digits
( 5 assumed, cannot be more)
Is it a bug? NO.
Value1 = 10.3 - 10.2 contains two numbers with 7 digits precision
10.3 is stored as 10.30000xxxx
10.2 is stored as 10.20000xxxx
where xxx is unknown to Float precision and will produce garbage after 7th
digit,
When difference is calculated it is performed on 7 digit - 7 digits
BUT:
10.y - 10.z will produce 00.[y-z]. -y=3, z=2
So the 2 digits are lost in the difference because 10 -10 = 00, and only
beacuqse of that.
What remains is 5 digit and is conform to the original initial Float
precision.
There is no bug at all, only a special case where the difference of two very
close numbers remove the 2 digits to the left.
The only solution is to have more than a float to store numbers, but even
a double will lose the 2 digits of the original double precision.
So this kind of operation will always lose precision in terms of digits, but
not in intriinsic precision ( the precision of the difference is ONE digit
in this case = 0.1)
And again, the difference here is far beyond the THREE digits precision of
the original numbers.
'Cannot undestand why you focus on such stupid things that are only logic
and does not involve any form of bug.
You will have the same problem using C or anything you want with 7 digits
float precision.
Sincerely,
Pierre Orphelin
www.sirtrade.com
TradeStation Technologies representative in France
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