```Date: Dec 29, 2012 3:08 PM
Author: Bob Hanlon
Subject: Re: Problem with Expand and Modulus in Mathematica 9?

Same difference on my MBA running OS X (10.8.2)\$Version"9.0 for Mac OS X x86 (64-bit) (November 20, 2012)"r1 = Expand[q1*p1*p2, Modulus -> m]1651432217 + 309632549 n + 188919829 n^2 + 1597920481 n^3\$Version"8.0 for Mac OS X x86 (64-bit) (October 5, 2011)"r1 = Expand[q1*p1*p2, Modulus -> m]1808010833 + 1914426603 n + 640234431 n^2 + 1087084730 n^3Bob HanlonOn Fri, Dec 28, 2012 at 5:37 AM, Ralf Hemmecke <hemmecke@gmail.com> wrote:> Can someone confirm that the following code gives different results for r1 for different versions of Mathematica and different operating systems. Or is this just an issue of my installation?>> ---BEGIN CODE---> m = 2147483629> q = -285170499> q1 = 1/q> q2 = PowerMod[q,-1,m]> Mod[q*q2, m]> p1 = 527660967 + 978421595*n> p2 = 1999783961 + 1587123368*n + 1965760814*n^2> r1 = Expand[q1*p1*p2,Modulus->m]> r2 = Expand[q2*p1*p2,Modulus->m]> s1 = Expand[Expand[q1*p1*p2],Modulus->m]> s2 = Expand[Expand[q2*p1*p2],Modulus->m]> ---END CODE>> Value of r1> Mathematica 8>     1808010833 + 1914426603*n + 640234431*n^2 + 1087084730*n^3>> Mathematica 9 (64bit Debian 6.0)>     1651432217 + 309632549*n + 188919829*n^2 + 1597920481*n^3>> Mathematica 9 (32bit Debian 6.0, 64bit CPU)>     1823075307 + 33175446*n + 2081129601*n^2 + 580053941*n^3>> The values of r2, s1, s2 agree with that of r1 as computed in Mathematica 8.>> Ralf>
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