Re: Problem with the zero-term of Fourier[]
- To: mathgroup at smc.vnet.net
- Subject: [mg19678] Re: Problem with the zero-term of Fourier[]
- From: adam.smith at hillsdale.edu
- Date: Thu, 9 Sep 1999 02:19:48 -0400
- Organization: Deja.com - Share what you know. Learn what you don't.
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I downloaded your files and tried them on my machine. (Dell Pentium II running Windows NT 4.0 and Mathematica Version 3.0.1.1x). My machine is limited in memory and I did not have sufficient memory to do the full 200,000 list - the computer kept bombing. But I was able to succefully get the correct result with a 100,000 element list. So maybe your problem is that you are right at the limits of the memory requirements to do 200,000 elements. Just a thought. My run for 100,000 is included below. Adam Smith A Problem 6. Sep. 1999 Real Example Read the data In[1]:= rawixr=ReadList["ixr.txt", Real]; Length[rawixr] Out[1]= 200000 Note: there seems to be some memory problem with trying to do 200,000 elements. So try shorter "subsets" In[2]:= ixr = Take[rawixr,100000]; Length[ixr] Out[2]= 100000 The Average In[3]:= (Plus@@ixr)/Length[ixr] Out[3]= -0.33816 The Zeroterm of the Fouriertransformation Remember, that Mathematica's F-transfomation is defined by 1/Sqrt[n] ... Therefore we calculate In[4]:= 1/Sqrt[Length[ixr]] Fourier[ixr] [[1]] Abs[%] Out[4]= -0.33816+0. I Out[5]= 0.33816 Sent via Deja.com http://www.deja.com/ Share what you know. Learn what you don't.