I can see ?. is biased and buggy, but many codes depend on this 'bug'. It is ok to implement a better ?. but only as another new primitive if there are enough user demand.
On Mon, Jul 20, 2020 at 12:22 AM Skip Cave <[email protected]> wrote: > It's clear that the statistical properties of ?. are repeatable, but they > are are > significantly different than ? > > mean"1(?."0,:?)2^i.50 > > 3.98766e12 1.46478e13 > > mean"1(?."0,:?)2^i.50 > > 3.98766e12 1.29535e13 > > mean"1(?."0,:?)2^i.50 > > 3.98766e12 1.67325e13 > > mean"1(?."0,:?)2^i.50 > > 3.98766e12 1.50923e13 > > mean"1(?."0,:?)100#1e3 > > 194 494.96 > > mean"1(?."0,:?)100#1e3 > > 194 538.78 > > mean"1(?."0,:?)100#1e3 > > 194 527.15 > > mean"1(?."0,:?)100#1e3 > > 194 513.06 > > The issue is whether that is a problem that needs to be fixed or not: > > > Skip Cave > Cave Consulting LLC > > > On Sun, Jul 19, 2020 at 11:02 AM Raul Miller <[email protected]> > wrote: > > > Well... I think we can agree that if ?. were replaced with 0: that > > that would not be random enough. > > > > So there has to be a better way of talking about this issue. > > > > If the current test suite is looking for hard coded results from ?. -- > > and I think it does -- then of course changing the ?. implementation > > would require careful update of the test suite, and this would become > > an ongoing future issue if the underlying implementation changed. So I > > think that that level of effort is what you are talking about?? > > > > Thanks, > > > > -- > > Raul > > > > On Sun, Jul 19, 2020 at 11:58 AM bill lam <[email protected]> wrote: > > > > > > Even ?. is not good, it won't change. Its purpose is to provide > > repeatable > > > random data for testing, it doesn't matter if it is not random enough. > > > > > > On Sun, Jul 19, 2020 at 11:41 PM Julian Fondren < > > [email protected]> > > > wrote: > > > > > > > On 2020-07-19 10:31, Brian Schott wrote: > > > > > Yes, I see the problem you are describing better now. > > > > > This behavior for powers of 2 is dissimilar with other power bases. > > > > > It suggests a flaw in the algorithm for ?. . > > > > > > > > > > > > > > > ?.2^11 > > > > > 1826 > > > > > ?.2^12 > > > > > 1826 > > > > > ?.2^13 > > > > > 1826 > > > > > NB. compared to the following > > > > > ?.3^11 > > > > > 35532 > > > > > ?.3^12 > > > > > 212679 > > > > > ?.3^13 > > > > > 1275561 > > > > > > > > #@~."1 (?."0 ,: ?.) 2^i.20 > > > > 7 18 > > > > #@~."1 (?."0 ,: ?.) 3^i.20 > > > > 13 20 > > > > > > > > It's only not as obvious with powers of 3. > > > > > ---------------------------------------------------------------------- > > > > For information about J forums see > http://www.jsoftware.com/forums.htm > > > > > > > ---------------------------------------------------------------------- > > > For information about J forums see http://www.jsoftware.com/forums.htm > > ---------------------------------------------------------------------- > > For information about J forums see http://www.jsoftware.com/forums.htm > > > ---------------------------------------------------------------------- > For information about J forums see http://www.jsoftware.com/forums.htm > ---------------------------------------------------------------------- For information about J forums see http://www.jsoftware.com/forums.htm
