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MathGroup Archive 2004

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Re: Re: Re: Finding the Fourier transform of discrete functions

  • To: mathgroup at smc.vnet.net
  • Subject: [mg52662] Re: Re: Re: Finding the Fourier transform of discrete functions
  • From: "Jens-Peer Kuska" <kuska at informatik.uni-leipzig.de>
  • Date: Tue, 7 Dec 2004 04:09:59 -0500 (EST)
  • Organization: Uni Leipzig
  • References: <cohi1d$1fh$1@smc.vnet.net> <200412011057.FAA19902@smc.vnet.net> <comgk7$7a2$1@smc.vnet.net> <200412030853.DAA26040@smc.vnet.net> <cos159$dl7$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Hi,

I think x_Integer is a pattern, that stand for any integer number,
it is a symbolic expression and the description "discrete" apply
not to a symbolic expressions.

Regards
  Jens

"DrBob" <drbob at bigfoot.com> schrieb im Newsbeitrag 
news:cos159$dl7$1 at smc.vnet.net...
> No, I think x_Integer is discrete.
>
> Obviously.
>
> Bobby
>
> On Fri, 3 Dec 2004 03:53:37 -0500 (EST), Jens-Peer Kuska 
> <kuska at informatik.uni-leipzig.de> wrote:
>
>> Hi,
>>
>> and you think that 1<=x<12 is discret, and not a infinite number
>> of continuous values ?? Strange !
>>
>> Regards
>>   Jens
>>
>> "DrBob" <drbob at bigfoot.com> schrieb im Newsbeitrag
>> news:comgk7$7a2$1 at smc.vnet.net...
>>>>> what is a "discrete function".
>>>>> if it is a function, the parameter is continuous and 
>>>>> FourierTransform[]
>>>>> compute the transformation.
>>>
>>> A discrete function is a function with a discrete domain.
>>>
>>> For instance, this is a discrete function on the obvious domain:
>>>
>>> f[x_Integer]/;1<=x<=12 = Sin@x
>>>
>>> It is NOT the Sin function, for the simple reason that the domain of a
>>> function (in math or mathematica) is part of its definition.
>>>
>>> Bobby
>>>
>>> On Wed, 1 Dec 2004 05:57:38 -0500 (EST), Jens-Peer Kuska
>>> <kuska at informatik.uni-leipzig.de> wrote:
>>>
>>>> Hi,
>>>>
>>>> what is a "discrete function". If it is discrete you have a array of
>>>> discrete data and Fourier[] compute the DFT of the array, if it is
>>>> a function, the parameter is continuous and FourierTransform[]
>>>> compute the transformation.
>>>>
>>>> Regards
>>>>   Jens
>>>>
>>>>
>>>> "Luca" <luca at nospam.it> schrieb im Newsbeitrag
>>>> news:cohi1d$1fh$1 at smc.vnet.net...
>>>>> I found out it's possible to determine the Fourier transform of a
>>>>> function. I tried to look for the discrete fourier transform in the
>>>>> guide, but I can find the item in the list without any explaination of
>>>>> the function. Is it possible to find the Fourier transform of a
>>>>> discrete function?
>>>>> Thanks to everyone.
>>>>>
>>>>> Luca
>>>>>
>>>>
>>>>
>>>>
>>>>
>>>>
>>>
>>>
>>>
>>> --
>>> DrBob at bigfoot.com
>>> www.eclecticdreams.net
>>>
>>
>>
>>
>>
>>
>
>
>
> -- 
> DrBob at bigfoot.com
> www.eclecticdreams.net
> 



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