Re: Wolfram, meet Stefan and Boltzmann
- To: mathgroup at smc.vnet.net
- Subject: [mg117327] Re: Wolfram, meet Stefan and Boltzmann
- From: AES <siegman at stanford.edu>
- Date: Tue, 15 Mar 2011 06:05:02 -0500 (EST)
- References: <ilfgt6$6t8$1@smc.vnet.net> <ilksd8$6aq$1@smc.vnet.net>
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
> Then evaluate your integral.
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.