Re: Wolfram, meet Stefan and Boltzmann

• To: mathgroup at smc.vnet.net
• Subject: [mg117349] Re: Wolfram, meet Stefan and Boltzmann
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Wed, 16 Mar 2011 06:24:52 -0500 (EST)

```Your initial set of timings for the integrals still seems
extraordinarily high.  For your first three inputs, the timings I get are:

0.000012
0.915221
1.94602

This is for:

\$Version
8.0 for Mac OS X x86 (64-bit) (February 23, 2011)
[i.e., 8.0.1]

MacBook 13", couple of months old
CPU: 2.26 GHz Intel Core 2 Duo
RAM: 2 GB 1067 MHz DDR3
OS: Mac OS X 10.6.6

On 3/15/2011 7:05 AM, AES wrote:
> In article<ilksd8\$6aq\$1 at smc.vnet.net>, Peltio<peltio at twilight.zone>
> wrote:
>
>> It is not clear if you had already started up a kernel before
>> evaluating the integral.
>> Try it this way: first thing first evaluate
>>    1+1
>
> Good idea.  Prepared a notebook with Input cells shown just below, Saved
> this notebook to desktop, Quit Mathematica.  Double-clicked the notebook, waited
> until Mathematica had re-started and notebook had Opened.  Selected All, hit
> Enter, got results below:
>
>     In[1]:= Timing[1+1//N]
>
>     Out[1]= {0.000017,2.}
>
>     In[2]:= Timing[Integrate[x/(Exp[x]-1),{x,0,Infinity}]]
>
>     Out[2]= {5.52206,\[Pi]^2/6}
>
>     In[3]:= Timing[Integrate[x^3/(Exp[x]-1),{x,0,Infinity}]]
>
>     Out[3]= {19.1595,\[Pi]^4/15}
>
> Did a Delete Output Cells, repeated the Select All and hit Enter, got
> following results:
>
>     In[4]:= Timing[1+1//N]
>
>     Out[4]= {0.000016,2.}
>
>     In[5]:= Timing[Integrate[x/(Exp[x]-1),{x,0,Infinity}]]
>
>     Out[5]= {0.059286,\[Pi]^2/6}
>
>     In[6]:= Timing[Integrate[x^3/(Exp[x]-1),{x,0,Infinity}]]
>
>     Out[6]= {0.085411,\[Pi]^4/15}
>
> Seems to be repeatable behavior.  No other messy stuff running on my
> MacBook.
>

--
Murray Eisenberg                     murray at math.umass.edu
Mathematics & Statistics Dept.
Lederle Graduate Research Tower      phone 413 549-1020 (H)
University of Massachusetts                413 545-2859 (W)
710 North Pleasant Street            fax   413 545-1801
Amherst, MA 01003-9305

```

• Prev by Date: Re: Wolfram, meet Stefan and Boltzmann
• Next by Date: mathematica fit data to inverse gamma distribution
• Previous by thread: Re: Wolfram, meet Stefan and Boltzmann
• Next by thread: Re: Wolfram, meet Stefan and Boltzmann