Re: Integration

[Patrick Alken]

You could also directly try the QAGI algorithm, though I have never used it:

https://www.gnu.org/software/gsl/doc/html/integration.html#qagi-adaptive-integration-on-infinite-intervals

On 3/5/20 6:49 AM, Patrick Alken wrote:
> Hello, did you try transforming the integral to have finite limits (i.e.
> https://www.youtube.com/watch?v=fkxAlCfZ67E). Once you have it in this
> form, I would suggest trying the CQUAD algorithm:
>
> https://www.gnu.org/software/gsl/doc/html/integration.html#cquad-doubly-adaptive-integration
>
> Patrick
>
> On 3/5/20 2:02 AM, Patrick Dupre wrote:
>> Hello,
>>
>>
>> Can I collect your suggestions:
>>
>> I need to make the following integration:
>>
>> int_a^b g(x) f(x) dx
>>
>> where a can be 0 of -infinity, and b +infinity
>> g(x) is a Gaussian function
>> f(x) = sum (1/((x-x0)^2 + g)) / (1 + S* sum (1 / ((x-x0)^2 + g)))
>>
>> Typically, f(x) is a fraction whose numerator is a sum of Lorentzians
>> and the denominator is 1 + the same sum of Lorentzians weighted by a factor.
>>
>> Thank for your suggestions
>>
>> ===========================================================================
>>  Patrick DUPRÉ                                 | | email: address@hidden
>>  Laboratoire interdisciplinaire Carnot de Bourgogne
>>  9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE
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>>
>>
>