From: Lorenzo Moneta <Lorenzo.Moneta_at_cern.ch>

Date: Fri, 25 Aug 2006 15:50:52 +0200

Date: Fri, 25 Aug 2006 15:50:52 +0200

Hi Andrew,

actually I noticed now you want the integral between 0 and inf. This is undefined, it is like getting the value of sin(x) for x=inf.

Best Regards,

Lorenzo

On Aug 25, 2006, at 12:49 PM, andreyk1_at_post.tau.ac.il wrote:

*> Dear Lorenzo,*

*>*

*> Thanks for solution, but this is not my case. The integral is too *

*> complicated to*

*> be done analitically. The only way is numerical calculation. *

*> Actually I can*

*> integrate between BesselJ zeroes and sum up these intervals, but it *

*> is not*

*> efficient.*

*>*

*> Andrew.*

*>*

*> Quoting Lorenzo Moneta <Lorenzo.Moneta_at_cern.ch>:*

*>*

*>> Hi Andrew,*

*>>*

*>> I don't know of a method for 2d with oscillatory function.*

*>> Hower, you should be able for a Bessel of order 0 to solve the*

*>> integral analytically,*

*>> using the Bessel J0 definition*

*>>*

*>> see http://en.wikipedia.org/wiki/Bessel_function*

*>>*

*>> Cheers,*

*>>*

*>> Lorenzo*

*>> On 24 Aug 2006, at 12:14, andreyk1_at_post.tau.ac.il wrote:*

*>>*

*>>>*

*>>>*

*>>> Dear rooters,*

*>>>*

*>>> I need to integrate over two dimensionl oscillating function*

*>>> (TMath::BesselJ(0,x*y), 0<x<inf, 0<y<inf). I use TF1 with*

*>>> IntegralMultiple, but*

*>>> the answer is not stable, a change in max_points leads to a*

*>>> different result. I*

*>>> tried to increas the number of max_points to 1e+6 but the result is*

*>>> still*

*>>> unstable. Is there some method of integrating over oscillating*

*>>> function with*

*>>> arbitry dimensions? (in my case it is dim = 2).*

*>>>*

*>>>*

*>>> Thanks a lot!*

*>>>*

*>>>*

*>>> Andrew*

*>>>*

*>>> ----------------------------------------------------------------*

*>>> This message was sent using IMP, the Internet Messaging Program.*

*>>>*

*>>>*

*>>*

*>>*

*>> +++++++++++++++++++++++++++++++++++++++++++*

*>> This Mail Was Scanned By Mail-seCure System*

*>> at the Tel-Aviv University CC.*

*>>*

*>*

*>*

*>*

*>*

*> ----------------------------------------------------------------*

*> This message was sent using IMP, the Internet Messaging Program.*

*>*

Received on Fri Aug 25 2006 - 15:53:21 MEST

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