# [R] FOURIER INTEGRALS IN R

A Achilleos maxaa at bristol.ac.uk
Tue May 5 16:17:36 CEST 2009

Ok thanks..

No, my function is not smooth.

Actually, I am dealing with an integral having the following form, for
example:

\int cos(tx) (1-t^2)^3 \exp(0.5*t^2) dt

I want to estimate this Fourier Cosine integral for a given value of x.

Thanks for the help.

AA

On Tue, May 5, 2009 2:34 am, andrew wrote:
> integrate offers some one-dimensional algorithms, but you need to
> start with a smooth function to get it to converge properly.  With a
> cosine integral, there may be certain routines that offer better value
> for money: the Clenshaw-Curtis integration, or perhaps the FFT.  You
> would have to recast your problem by doing some sort of substitution.
>
> Perhaps post some latex code to show the exact type of integral you
> are wanting to calculate.
>
> Regards,
>
> On May 5, 6:32 am, "Achilleas Achilleos" <ma... at bristol.ac.uk> wrote:
>> Hi,
>>
>> I am wondering whether there exist any function in R (any package) that
>> calculates Fourier Integrals.
>>
>> Particularly, I am interested for estimation of a Cosine Fourier
>> integral...
>>
>> I would be much obliged if you could help me on this..
>>
>> Thanks.
>>
>> Andreas
>>
>> --
>>
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>
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