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Interesting, but very fuzzy logic (pun untended, considering the
source). I have no more time to waste arguing with you on this.
YOU ARE WRONG!
To explain it in extreme detail one more time, take an extremely
simple case. Assume we have two values and we want to find the
difference between the values.
Assume that if we had perfect arithmetic, the two values would be:
10323.45026584125452... and 10321.20065325413...
TradeStation will represent each number with precision of one part in
10^7 so TradeStation will represent these values as:
10323.450xxxx and 10321.200xxxx
where the xxxx are numbers with no accuracy.
So when we see this and since we do not know the true numbers, all we
know is that the true value might be anywhere within a window of
0.001 on either side of the above values:
10323.449xxxx and 10321.199xxxx Minimum
10323.451xxxx and 10321.201xxxx Maximum
So the difference between the two numbers can have values ranging
from:
10323.449xxxx - 10321.201xxxx = 2.248xxxx Minimum
10323.451xxxx - 10321.199xxxx = 2.252xxxx Maximum
So the maximum uncertainty in the difference is:
Uncertainty: 0.004xxxx
The uncertainty as a ratio to the value = 0.004 / 2.25 = 0.0018
This is 1.8 parts in 10^3
So the TradeStation precision of one part in 10^7 in the ORIGINAL
VALUES caused an error of 1.8 parts in 10^3 in the difference
between the two values.
Certainly, TradeStation can represent the difference to seven
significant places of precision:
2.248xxxx Minimum
2.252xxxx Maximum
but all of the places shown by the "xxxx" have no accuracy because of
the ERROR IN REPRESENTING THE ORIGINAL NUMBERS.
You say:
"...and that in any case, the TS precision do not damage the
precision of the calculus."
I repeat: YOU ARE WRONG!
You clearly do not understand this and I have exhausted my methods of
explaining it to you. If ANY of the thousand or so people on this
list think Pierre is correct, please tell us...
Bob Fulks
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