Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2004
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2004

[Date Index] [Thread Index] [Author Index]

Search the Archive

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


>> description "discrete" apply not to a symbolic expressions.

Maybe not, but it does apply to mathematical functions and their domains.

See for instance:

http://www.2dcurves.com/discrete/discrete.html
http://caltechcdstr.library.caltech.edu/5/
http://www.sparknotes.com/math/algebra2/discretefunctions/terms/term_B.2.html
http://portal.acm.org/citation.cfm?id=225072
http://mathforum.org/epigone/sci.math.research/grorrinroi
http://www.informs.org/Conf/NewOrleans95/TALKS/MC26.1.html
http://www.ds.unifi.it/VL/VL_EN/dist/dist1.html

(I could go on all day.)

Bobby

On Tue, 7 Dec 2004 04:09:59 -0500 (EST), Jens-Peer Kuska <kuska at informatik.uni-leipzig.de> wrote:

> 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
>>
>
>
>
>
>



-- 
DrBob at bigfoot.com
www.eclecticdreams.net


  • Prev by Date: Re: Re: A problem of numerical precision
  • Next by Date: Integration and Summation of Piecewise Functions
  • Previous by thread: Re: Re: Re: Finding the Fourier transform of discrete functions
  • Next by thread: Re: Finding the Fourier transform of discrete functions