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Re: evaluating functions and displaying results numerically

• To: mathgroup at smc.vnet.net
• Subject: [mg126262] Re: evaluating functions and displaying results numerically
• From: Murray Eisenberg <murray at math.umass.edu>
• Date: Fri, 27 Apr 2012 06:52:42 -0400 (EDT)
• Delivered-to: l-mathgroup@mail-archive0.wolfram.com
• References: <201204260932.FAA05740@smc.vnet.net>
• Reply-to: murray at math.umass.edu

Kindkly post your code about the sum directly in an e-mail message (and 
be sure to use Copy As...Plain Text from Mathematica). Trying to deal 
with code shown just in a pdf is not easy.

On 4/26/12 5:32 AM, Alexei Boulbitch wrote:
> Thanks for the replies. I can go along with all your explanations for the Sin function, even though I havent had this interpretation of results from Mathematica before. I never had to use the N option before. What about my second enquire, reproduced below:
>
> In another instance, I have a summation of about 1000 terms defined as
>
> a function of 3 arguments. When I use numerical arguments to calculate the summation, instead of
>
> Mathematica calculating a numerical result it generates a symbolic
>
> output with all 1000 terms.
>
> It doesnt make sense that Mathematica chooses to do the whole thing symbolically. I have made similar calculations before, and Mathematica performed the calculation numerically. I presume that I have enabled some sort of symbolic calculation mode, but I cannot figure out where. I am attaching a a link to a pdf file showing a image of the generated result for my function called "Absorption". The other functions called by Absorption are defined prior to the definition of Absorption. I just want to show the type of result generated. Also, If I want to plot my function Absorption relative to one of the arguments, Mathematica just doesnt plot it.
>
> Best regards
>
> The output image is in the google docs file below
>
> https://docs.google.com/open?id=0Bw08G8QtolpXUDBnQUswdXUyVE0
>
>
>
> It looks possible that you have some function or variable in your sum that has not been defined before and, therefore, Mathematica treats the whole thing analytically.
>> From the fragment you showed in the link it was difficult to see which one it could be. May be Ref?
> If you write your functions directly in the post, it will be easier to help you.
>
> Have fun, Alexei
>
> Alexei BOULBITCH, Dr., habil.
> IEE S.A.
> ZAE Weiergewan,
> 11, rue Edmond Reuter,
> L-5326 Contern, LUXEMBOURG
>
> Office phone :  +352-2454-2566
> Office fax:       +352-2454-3566
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>
> e-mail: alexei.boulbitch at iee.lu<mailto:alexei.boulbitch at iee.lu>
>
>
>

-- 
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

• References:
  • Re: evaluating functions and displaying results numerically
    • From: Alexei Boulbitch <Alexei.Boulbitch@iee.lu>