Re: Fourier? (Q)

• To: mathgroup at smc.vnet.net
• Subject: [mg2628] Re: Fourier? (Q)
• From: Robert Knapp <rknapp>
• Date: Sat, 30 Mar 1996 02:46:44 -0500
• Organization: Wolfram Research, Inc.
• Sender: owner-wri-mathgroup at wolfram.com

```mrsma at uno.edu wrote:
>
> greetings:
>
> when i tried to go through the Fourier examples as per pgs 679-681 in the Mma bible;
>
> Mma kindly returned the following:
...
> Fourier[data]
> Out[67]=
> Fourier[{1, 1, 1, 1, -1, -1, -1, -1}]
...
>
The command Fourier in Version 2.2 was not designed to work for a list
of exact numbers.  In the next version of Mathematica, your examples
will work by converting to machine numbers automatically, which is what
most people want.  However, in the meantime, what you need to do is put
N[] around the list so the inputs are inexact:

In[1]:=
data={1,1,1,1,-1,-1,-1,-1};
In[2]:=
Fourier[N[data]]
Out[2]=
{0. + 0. I, 0.707107 + 1.70711 I, 0. + 0. I,

0.707107 + 0.292893 I, 0. + 0. I,

0.707107 - 0.292893 I, 0. + 0. I,

0.707107 - 1.70711 I}

Rob Knapp
Wolfram Research, Inc.

> m. r.

--
Rob Knapp
Wolfram Research, Inc.

http://www.wri.com/~rknapp

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```

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