Android with armv7 cpu are 32 bit, with armv8 cpu are 64 bit. They give different results for RNG.
32 vs 64 bit can be checked by the global noun IF64 On Thu, Feb 6, 2020, 9:18 PM 'Rob Hodgkinson' via Programming < programm...@jsoftware.com> wrote: > Hi Arnab, further to Pascal’s note I would suggest the following approach: > Set the random seed for the RNG to a value you desire (see the > Foreign Conjunction 9!:1 ) > Then call ?n as you wish to produce a sequence as many times as > you wish > > Repeat sequence above to reproduce from a preset seed, for example: > > First run: > 9!:1 ] 3581 NB. Set RNG Seed to 3581 > > ?8 > 2 > ?100 100 100 > 10 28 71 > ?8 > 5 > > Now repeat: > 9!:1 ] 3581 NB. Reset RNG Seed to 3581 again to reproduce above > > ?8 > 2 > ?100 100 100 > 10 28 71 > ?8 > 5 > > I believe (untested) this approach should produce the same results across > your students devices. > > Best, Rob > > > On 7 Feb 2020, at 12:14 am, 'Pascal Jasmin' via Programming < > programm...@jsoftware.com> wrote: > > > > The initial seed is the same each time you start J. > > ?. differs on 32 and 64 bit systems, with default generator. > > On Thursday, February 6, 2020, 07:21:31 a.m. EST, Arnab Chakraborty < > damd...@gmail.com> wrote: > > > > Dear all, > > > > For my class of about 30 students armed with JAndroid 901, I had planned > to > > use ?. to generate a random matrix which should be same for everybody. To > > start with, I asked everybody to try > > > > ?. 100 > > > > Some got 46, others got 93. No other values. Next, someone noticed that > if > > they repeatedly type > > > > ? 100 > > > > then many are getting the SAME sequence of "random" numbers. Hence my > > question: > > > > 1) Is there a way to produce predictable "random numbers" across > different > > machines (all running Jandroid 901_*, where the *'s may differ)? > > > > 2) Is there some way to get the initial seed from, say, the system time > in > > millisecond (or something like that)? > > > > Thanks a lot. > > > > Arnab. > > > > PS: BTW, my students are loving J! > > ---------------------------------------------------------------------- > > 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
