Re: Re: Number of Differing Digits & Another Problem (want to

*To*: mathgroup at smc.vnet.net*Subject*: [mg76388] Re: [mg76340] Re: [mg76310] Number of Differing Digits & Another Problem (want to*From*: DrMajorBob <drmajorbob at bigfoot.com>*Date*: Mon, 21 May 2007 05:58:43 -0400 (EDT)*References*: <4047165.1179646026504.JavaMail.root@m35>*Reply-to*: drmajorbob at bigfoot.com

Clear[bitDifference] bitDifference[a_, a_] = 0; bitDifference[a_, b_] /; a > b := Block[{one = IntegerDigits[a, 2], two}, two = IntegerDigits[b, 2, Length@one]; Plus @@ Abs[one - two] ] bitDifference[a_, b_] := bitDifference[b, a] Bobby On Sun, 20 May 2007 01:23:41 -0500, Bob Hanlon <hanlonr at cox.net> wrote: > Since you intend to count the bit differences your function needs to b= e = > modified to > > Clear[BitDifferences]; > BitDifferences[a_,b_,n_]:= > n-Count[Equal@@@ > Thread[{IntegerDigits[a,2,n],IntegerDigits[b,2,n]}],True]; > > t1=Table[BitDifferences[a,b,6],{a,-16,16},{b,-16,16}]; > > I would use > > Clear[BitDifferences]; > BitDifferences[a_,b_]:=Module[ > {n=Length[IntegerDigits[Max[Abs[{a,b}]],2]]}, > n-Count[IntegerDigits[a,2,n]-IntegerDigits[b,2,n],0]]; > > t2=Table[BitDifferences[a,b],{a,-16,16},{b,-16,16}]; > > t1==t2 > > True > > > Bob Hanlon > > ---- VenDiddy at gmail.com wrote: >> I just purchased a copy of Mathematica and I've been learning it for >> about a week now. You can expect that I will be posting a lot of >> questions. One thing I've noticed is that there are so many different= >> ways to do the same thing! >> >> Here is a function I came up with that calculates how many binary >> digits two numbers differ in: >> >> BitDifferences[a_, b_, n_] := >> Count[Equal @@@ >> Thread[{IntegerDigits[a, 2, n], IntegerDigits[b, 2, n]}], True] >> >> For example 5 = 101 differs from 6 = 111 by one digit (the middle= >> digit). >> >> I want to see how you would do it so I can broaden my Mathematica >> perspective. >> >> Thanks. >> >> > > > -- = DrMajorBob at bigfoot.com