List Commands Library for 50g

[DavidM]

(11-21-2017 05:43 AM)Thomas Okken Wrote:  ...
As long as you truncate the result from RAN or RAND to 12 digits after the decimal, this is all fine... but it seems to me like you shouldn't have to. I think this behavior is wrong. RAN and RAND should just chop off the last 3 digits of the 15-digit seed, divide the result by 10^15, and thus return a truly uniformly distributed number on the inverval [0, 1).

Other than this being a rare mathematical boo-boo by HP, is there any other explanation why these functions work the way they do?

I've been hoping others would respond to the above, because the truncation method you advocate in the first paragraph above is exactly what I used for the LSHUF command in the library (it also does a range check, but that's a different issue altogether). I fear that the very people who are likely to have insight to this are no longer following this thread. Perhaps a separate posting of your observations might get more readers.

As to the "what were they thinking" issue, could it simply be that they were attempting to retain as many of the internal 15 digits generated as possible? I'm not qualified to comment on the efficacy of that approach in this instance, but it would at least be consistent with the general operation of most internal functions.

Regarding the exclusion of 0 from the possible results of the internal functions, I find it odd as well that the documentation is so out of sync with the implementation. The fact that the documentation is inconsistent implies that at least one person was looking at that somewhere along the lines, and you'd think that it would have been addressed properly as a result.