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Hi Tomasz,
Sunday, April 18, 2004, 9:10:11 AM, you wrote:
TJ> You either did not read what I wrote before or you just don't
TJ> want to understand that your MS database is in 32 bit floating
TJ> point format and it means that only 7 (SEVEN) digits are
TJ> accurate NO MATTER what.
TJ> http://research.microsoft.com/~hollasch/cgindex/coding/ieeefloat.html
TJ> This is the limitation of IEEE 32 bit format.
TJ> If you are getting the data from MS database YOU CAN NOT IMPROVE accuracy
TJ> above 7 digits.
I read, but I do not understand.
For example: I have a fair number of stocks that often do volumes in
the 8 digit range (above 9,999,999). When I enter these volumes in
my MS database, I never get "rounding errors" there. The numbers
remain exactly as I enter them. Yet, this is more than 7 digits, but
there is no "rounding error" here. So, what am I missing?
TJ> Now 32 bit INTEGER (used by AB) provides MORE ACCURACY, as the maximum
TJ> positive number that can be accurately represented is 2147483648
TJ> (THATS 9+ DIGITS). And that is 2 DIGITS ABOVE accuracy of your MS source.
TJ> Now if you divide everything by 10 (and you loose the least significant integer digit)
TJ> you still have 8 digits which still provides MORE accuracy
TJ> than your SOURCE MS database has.
I have decided to go at it this way:
I will export all the TOPIX volume to EXCEL, and multiply it by .001.
Then I will round it to zero decimal places, which will eliminate the
MS-induced "rounding error" caused sometimes when I enter these huge
digits in the first place. I will have a 7-digit number for TOPIX
volume, which I will then import back into my MS database,
overwriting the original number. This will produce a clean chart in
AB, eliminate the "rounding error" in the MS database, and basically
solve things -- at least then (multiplying by .001) the commas will
be in the right place, something that would drive me crazy otherwise.
But . . . I would like to have a notation on my TOPIX chart (only)
that I have done this. Eventually, I will get used to seeing three
digits less in the TOPIX volume, and mentally compensate, but for now
I really want to have that notation. But I am not sure how to write
it. I may do the same for ^N225 volume; the day it breaks the
numerical ceiling is probably not too far away.
Yuki
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