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Re: binomial sum bug

  • To: mathgroup at smc.vnet.net
  • Subject: [mg82625] Re: binomial sum bug
  • From: "Jack Kennedy" <jack at realmode.com>
  • Date: Fri, 26 Oct 2007 05:27:02 -0400 (EDT)
  • References: <ffpq7m$lf7$1@smc.vnet.net> <47208ABE.3070908@gmail.com>

So, does Wolfram offer patches to fix their bugs or is it
expected that users simply upgrade to the current version?

Jack

On 10/25/07, Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com> wrote:
>
> Jack Kennedy wrote:
>
> > In:  Sum[Binomial[5,2k],{k,0,5}]
> > Out: 16
> >
> > In:  Sum[Binomial[n,2k],{k,0,n}] /. n->5
> > Out:  -16
> >
> > What the?
> >
> > This has been addressed before
> > about a year ago and a work around was posted
> > but I have two questions:
> >
> > 1. Was it declared a bug by Wolfrram, and
> > 2. In general does Wolfram issue bug fixes, and specifically is there
> > a patch for this problem?
> >
> > $Version = 5.1 for Microsoft Windows (October 25, 2004)
>
> Apparently, this bug has not been fixed in version 5.2. Version 6.0.1
> works as expected, however.
>
> In[1]:= Sum[Binomial[5, 2 k], {k, 0, 5}]
>
> Out[1]= 16
>
> In[2]:= Sum[Binomial[n, 2 k], {k, 0, n}] /. n -> 5
>
> Out[2]= 16
>
> In[3]:= $Version
>
> Out[3]= "6.0 for Microsoft Windows (32-bit) (June 19, 2007)"
>
> (* Version 5.2 *)
> In[1]:=
> Sum[Binomial[5,2k],{k,0,5}]
>
> Out[1]=
> 16
>
> In[2]:=
> Sum[Binomial[n,2k],{k,0,n}]/.n\[Rule]5
>
> Out[2]=
> -16
>
> In[3]:=
> $Version
>
> Out[3]=
> 5.2 for Microsoft Windows (June 20, 2005)
>
> Regards,
> --
> Jean-Marc
>

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So, does Wolfram offer patches to fix their bugs or is it<br>expected that users simply upgrade to the current version?<br><br>Jack<br><br><div><span class="gmail_quote">On 10/25/07, <b class="gmail_sendername">Jean-Marc Gulliet
</b> &lt;<a href="mailto:jeanmarc.gulliet at gmail.com">jeanmarc.gulliet at gmail.com</a>&gt; wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
Jack Kennedy wrote:<br><br>&gt; In:&nbsp;&nbsp;Sum[Binomial[5,2k],{k,0,5}]<br>&gt; Out: 16<br>&gt;<br>&gt; In:&nbsp;&nbsp;Sum[Binomial[n,2k],{k,0,n}] /. n-&gt;5<br>&gt; Out:&nbsp;&nbsp;-16<br>&gt;<br>&gt; What the?<br>&gt;<br>&gt; This has been addressed before
<br>&gt; about a year ago and a work around was posted<br>&gt; but I have two questions:<br>&gt;<br>&gt; 1. Was it declared a bug by Wolfrram, and<br>&gt; 2. In general does Wolfram issue bug fixes, and specifically is there
<br>&gt; a patch for this problem?<br>&gt;<br>&gt; $Version = 5.1 for Microsoft Windows (October 25, 2004)<br><br>Apparently, this bug has not been fixed in version 5.2. Version 6.0.1<br>works as expected, however.<br><br>
In[1]:= Sum[Binomial[5, 2 k], {k, 0, 5}]<br><br>Out[1]= 16<br><br>In[2]:= Sum[Binomial[n, 2 k], {k, 0, n}] /. n -&gt; 5<br><br>Out[2]= 16<br><br>In[3]:= $Version<br><br>Out[3]= &quot;6.0 for Microsoft Windows (32-bit) (June 19, 2007)&quot;
<br><br>(* Version 5.2 *)<br>In[1]:=<br>Sum[Binomial[5,2k],{k,0,5}]<br><br>Out[1]=<br>16<br><br>In[2]:=<br>Sum[Binomial[n,2k],{k,0,n}]/.n\[Rule]5<br><br>Out[2]=<br>-16<br><br>In[3]:=<br>$Version<br><br>Out[3]=<br>5.2 for Microsoft Windows (June 20, 2005)
<br><br>Regards,<br>--<br>Jean-Marc<br></blockquote></div><br>

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