Re: Mathemaica 5.2 are the 64 Bit an illusion !!!....?

*To*: mathgroup at smc.vnet.net*Subject*: [mg60683] Re: Mathemaica 5.2 are the 64 Bit an illusion !!!....?*From*: Dave Seaman <dseaman at no.such.host>*Date*: Sat, 24 Sep 2005 02:55:26 -0400 (EDT)*Organization*: Information Technology at Purdue*References*: <dgr2cl$85f$1@smc.vnet.net> <dgtivg$266$1@smc.vnet.net> <dh0el3$q65$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

On Fri, 23 Sep 2005 08:33:39 +0000 (UTC), LumisROB wrote: > On Thu, 22 Sep 2005 06:29:04 +0000 (UTC), Dave Seaman ><dseaman at no.such.host> wrote: >> >>Incorrect. First of all, your arithmetic is wrong, since 10^4 * 10^4 * 8 is >>only 800 MB, not 4 GB. Secondly, I have created arrays bigger than 9 GB using >>Mathematica 5.2 on a Mac G5. > ....and 800 MB * 4 = 3.2 GB (Attention, I have expressly said 4 > matrixes ). > What type of matrixes? I hope is not those all of 0 as you had > already told me in another newsgroup (sci.math.symbolic). Test please > using Table and an expression of the single element an a little more > complicated (or that from me suitable): it would interest me to know > the result in this case. > However, for the precision and correctness I have not verified on Mac > but only on WinXP and Linux. As I have already explained, I used "0.", not "0". The difference is that 0. takes the same amount of space as a Random[] value, while 0 takes only half as much. I don't see the point of generating 4 matrices for the test instead of a single matrix that is 4 times as large. Perhaps it makes a difference in the paging performance, but it shouldn't make a difference in whether the calculation is able to complete or not. Since my previous posting I have upgraded to Mathematica 5.2 on several 64-bit systems (AIX, SunOS, and Linux). I couldn't get the computation to finish on any of those. The IBM SP version at least ran quite a bit longer than Mathematica 5.1 did on the same platform, but so far only the Mac OS X version has performed the test successfully. -- Dave Seaman Judge Yohn's mistakes revealed in Mumia Abu-Jamal ruling. <http://www.commoncouragepress.com/index.cfm?action=book&bookid=228>