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: pdu...@gmx.com >> Laboratoire interdisciplinaire Carnot de Bourgogne >> 9 Avenue Alain Savary, BP 47870, 21078 DIJON Cedex FRANCE >> Tel: +33 (0)380395988 >> =========================================================================== >> >> >
