Re: RealDigits bug?

*To*: mathgroup at smc.vnet.net*Subject*: [mg45910] Re: RealDigits bug?*From*: drbob at bigfoot.com (Bobby R. Treat)*Date*: Thu, 29 Jan 2004 05:35:34 -0500 (EST)*References*: <bv00g1$je7$1@smc.vnet.net> <bv2g1t$68$1@smc.vnet.net> <bv82tq$i97$1@smc.vnet.net>*Sender*: owner-wri-mathgroup at wolfram.com

I'm using Version 5.0.1 under WinXP and OS X, and I just reproduced it again on both machines. It's a rather glaring bug. pisot = N[((1/3)*((1/2)*(27 + 3*Sqrt[69]))^ (1/3) + (2/(27 + 3*Sqrt[69]))^ (1/3))^27351, 6000]; Frequencies[First[RealDigits[ pisot]]] {{2086, 0}, {422, 1}, {427, 2}, {434, 3}, {467, 4}, {444, 5}, {452, 6}, {447, 7}, {437, 8}, {381, 9}, {3, 10}} Bobby adam.smith at hillsdale.edu (Adam Smith) wrote in message news:<bv82tq$i97$1 at smc.vnet.net>... > Bobby, > > What version of Mathematica are you using? I am running Version 4.1 > and it does not include 10 in the Frequencies list > > In[3]:= > Frequencies[First[RealDigits[ pisot]]] > > > Out[3]= > {{2089,0},{422,1},{427,2},{434,3},{467,4},{444,5},{452,6},{447,7},{437, > 8},{381,9}} > > > In response to Enrique. I suspect that the failure is related to a > misunderstanding of the N[] function. In particular look in the Help > for N[] and study the $MaxMachineNumber and $MaxPrecision. Since your > pisot is on the order of 10^3340, you may be running into truncation > errors with N[]. On my machine $MaxMachineNumber is around 10^308. > Since pisot is clearly much greater than this, I would expect > truncation errors. > > Adam Smith > > drbob at bigfoot.com (Bobby R. Treat) wrote in message news:<bv2g1t$68$1 at smc.vnet.net>... > > I don't know whether the equality should be true, but it's very clear > > that 10 isn't a base-10 digit! > > > > Frequencies[First[RealDigits[ > > pisot]]] > > {{2086, 0}, {422, 1}, > > {427, 2}, {434, 3}, > > {467, 4}, {444, 5}, > > {452, 6}, {447, 7}, > > {437, 8}, {381, 9}, {3, 10}} > > > > Bobby > > > > Enrique Zeleny <ezeleny at fismat1.fcfm.buap.mx> wrote in message news:<bv00g1$je7$1 at smc.vnet.net>... > > > This is wrong: > > > > > > In[1]:= pisot = N[((1/3)*((1/2)*(27 + 3*Sqrt[69]))^(1/3) + (2/(27 + > > > 3*Sqrt[69]))^(1/3))^27351, 6000]; > > > > > > In[2]:= pisot == FromDigits[RealDigits[pisot]] > > > > > > Out[2]:= False > > > > > > If you look at the value returned by RealDigits[pisot] contains three > > > 10's!!! > > > > > > > > > Enrique Zeleny > > > Universidad Autonoma de Puebla > > > Mexico