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MathGroup Archive 2007

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Re: Optimisation of FourierCoefficients

  • To: mathgroup at smc.vnet.net
  • Subject: [mg75244] Re: Optimisation of FourierCoefficients
  • From: dh <dh at metrohm.ch>
  • Date: Sat, 21 Apr 2007 23:16:25 -0400 (EDT)
  • References: <f09gh3$12c$1@smc.vnet.net>


Hi Edmund,

The arguments of FindMinimum are evaluated before fed to FindMinimum. To 

prevent this, declare a function that only takes numerical arguments, e.g.:

fun[y_/;NumericQ[y]]:=Abs[Fourier[{y,1}][[1]]];

FindMinimum[fun[y],{y,2}]

hope this helps, Daniel



Edmund wrote:

> I want to find the minimum of a Fourier-Coefficient as a function of the 

> input values.

> 

> FindMinimum[Abs[Fourier[{ y, 1}][[1]]], {y, 2}]

> 

> The actual problem is a little more complicated, but even this simple 

> statements gives the error messages I can't understand.

> 

> Fourier::fftl: Argument {y, 1} is not a non-empty list or rectangular array 

> \

> of numeric quantities.

> 

> 

> Any suggestion ?

> 

> best regards

> 

> Edmund

> 

> 

> 




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