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## Re: [Help-gsl] Integration involving Bessel Function

**From**: |
ptribedy |

**Subject**: |
Re: [Help-gsl] Integration involving Bessel Function |

**Date**: |
Fri, 4 Jun 2010 14:43:53 -0400 |

**User-agent**: |
SquirrelMail/1.4.19 |

Dear Sir,
thank you for the suggestion.
Yes, I tried "gsl_integration_qagiu" , it also couldn't handle the
oscillation and finally giving a very large +ve or -ve value.
I am doing multiple integrations(using say gsl_integration_qag) between
the zero's of J0(x) and summing up the series using some force convergence
method. Its is very slow method.
My integral is :
I(k)= \int_0^\infty [dx x J0(kx) F(x) ].
comes from
I(k)= 1/(2pi)*\int_0^\infty [ d^2x exp(i k.x) F(x)]
which is has a form very similar to a Fourier-Transform integration.
is there any other efficient method to handle such integral?
regards,
Prithwish
>* At Wed, 2 Jun 2010 06:33:16 -0400,*
>* address@hidden wrote:*
>*> I am a beginer with gsl and I am trying to do an integration of the*
>*> form:*
>*>*
>*> \int_0^\infty [ x J0(x) F(x) ].*
>*>*
>*> J0(x) being oscillatory makes the integrtal +ve and -ve within its*
>*> consecutive zero's. Form of F(x) is such that the overall integrand is a*
>*> decaying function of x.*
>*>*
>*> How to handle this type of integration using gsl.*
>*>*
>*> I tried using "gsl_integration_qag", but its not giving the correct*
>*> results.*
>*>*
>
>* Did you try gsl_integration_qagiu (infinite upper limit)?*
>