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MathGroup Archive 2004

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Re: simple bug about Sum/Product function?

  • To: mathgroup at smc.vnet.net
  • Subject: [mg46727] Re: simple bug about Sum/Product function?
  • From: "David W. Cantrell" <DWCantrell at sigmaxi.org>
  • Date: Wed, 3 Mar 2004 02:30:37 -0500 (EST)
  • References: <c237r8$ie9$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

"MATUDA Yuko" <matsuda.yuko at acm.org> wrote:
> Try the following simple expressions in Mathematica(ver5)
>
> Sum[1, {1000001}]
> Product[1, {1000001}]
>
> There are no problems in ver 4.2.

I'm rather surprised that they work as you wish in version 4.2, considering
that no index was specified. And considering that, it doesn't surprise me
that they don't work in version 5.

But here's a genuine Product bug in version 5.0.0:

In[1]:= Product[1, {i, 1000001}]

Out[1]= Product[1, {i, 1, 1000001}]

In[2]:= FullSimplify[%]

Out[2]= Product[1, {i, 1, 1000001}]

For smaller values of the upper limit of the index, the output seems always
to be 1, as desired. The bug seems to occur for 1000001 and larger integer
values of the upper limit of the index. Note however that, as desired,

In[3]:= Product[1, {i, Infinity}]

Out[3]= 1

I have found no corresponding Sum bug in version 5.0.0. For example, as
desired,

In[4]:= Sum[1, {i,1000001}]

Out[4]= 1000001


Has the Product bug mentioned above been fixed in version 5.0.1?

David Cantrell


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