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Re: Fourier? (Q)

  • To: mathgroup at smc.vnet.net
  • Subject: [mg3648] Re: [mg3602] Fourier? (Q)
  • From: hagai at helix.nih.gov (Hagai Agmon-Snir)
  • Date: Sun, 31 Mar 1996 00:52:27 -0500
  • Sender: owner-wri-mathgroup at wolfram.com

>greetings:
>
>when i tried to go through the Fourier examples as per pgs 679-681 in the
>Mma bible;
>
>Mma kindly returned the following:
>In[65]:=
>?Fourier
>Fourier[list] finds the discrete Fourier transform of a list
>   of complex numbers.
>In[66]:=
>data={1,1,1,1,-1,-1,-1,-1}
>Out[66]=
>{1, 1, 1, 1, -1, -1, -1, -1}
>In[67]:=
>Fourier[data]
>Out[67]=
>Fourier[{1, 1, 1, 1, -1, -1, -1, -1}]

You have a point. Here what solves it:
In[29]:=
data={1.,1.,1.,1.,-1.,-1.,-1.,-1.}
Out[29]=
{1., 1., 1., 1., -1., -1., -1., -1.}
In[30]:=
Fourier[data]
Out[30]=
{0. + 0.*I, 0.7071067811865479 + 1.707106781186547*I,

  0. + 0.*I, 0.7071067811865474 + 0.2928932188134521*I,

  0. + 0.*I, 0.7071067811865475 - 0.2928932188134524*I,

  0. + 0.*I, 0.7071067811865474 - 1.707106781186547*I}


What few dots can do (especially if they are not documented}! I never
realized before that Fourier would not accept integers.

Hagai

>>>>>>>>>>>>>>>>>>  ================================  <<<<<<<<<<<<<<<<<
Hagai Agmon-Snir                                    Tel: (301) 496-9972
                                                         (301) 496-4325
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E-mail: hagai at helix.nih.gov         WWW: http://mrb.niddk.nih.gov/hagai
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