Re: Still bug in Random

*To*: mathgroup at smc.vnet.net*Subject*: [mg61777] Re: Still bug in Random*From*: Joseph Gwinn <JoeGwinn at comcast.net>*Date*: Sat, 29 Oct 2005 01:32:43 -0400 (EDT)*References*: <djsk93$8lr$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

In article <djsk93$8lr$1 at smc.vnet.net>, "Pedrob P.B. de Oliveira" <pedrob at mackenzie.br> wrote: > I've just tried Mathematica 5.2 in respect to an old bug in Random[ ], as > pointed out in the Mathgroup posting > > Subject: [mg61777] bug in Random > From: Veit Elser <ve10 at cornell.edu> To: mathgroup at smc.vnet.net > > and the bad news is that the bug remains... > > The problem is a correlation in the random numbers generated from running > the expressions > > r=Table[Random[Integer,{1,2^62}],{10^5}]; > Union[Table[r[[i]]+r[[i+24]]-r[[i+20]],{i,10^5-24}]] > > which, surprisingly, yields simply > > {-2147483647, 1, 2147483649, 4611686016279904256,4611686018427387904, > 4611686020574871552} I wonder if the integer range of Random[] really supports integers larger than 32 bits. If not, a random integer on the range 0..2^62 may not be very random. If you really do need 62-bit integers, it may work better to make them from two 32-bit random integers. Joe Gwinn