hi, Thanks again for taking pain in trying to help me. I have understood the matter with poisson distribution. I had not chosen a good example. as I had just written to Martin, The problem is not just dealing with a specific distribution. I am interested in all distributions from which I can sample within a range (min, max). And I still would like to know if the solution f(r) = a + (b - a) * r would work for any distribution returning a double or it should be the output of a generator from a uniform distribution?
thanks again, Mohd > -----Ursprüngliche Nachricht----- > Von: "Daniel J Farrell" <[EMAIL PROTECTED]> > Gesendet: 18.06.08 11:29:46 > An: Mohammad Khaleghi <[EMAIL PROTECTED]> > CC: [email protected] > Betreff: Re: [Help-gsl] Random numbers within some ranges in the domain using > different distributipons? > Hello, > > I think gsl_ran_poisson (const gsl_rng * r, double mu) returns the 'k' > number (i.e. then number of occurrences associated with that > probability generated by 'r'). This is an educated guess based on the > fact that p(k,lambda) and you is entering p() and lambda into the > above function. > > You want to sample the poisson distribution in a given range of what? > Do you have a lambda and a k value? Or do you just have a lambda? > > Cheers, > > Dan/ > > On 17 Jun 2008, at 17:44, Mohammad Khaleghi wrote: > > > Hello Dan, > > > > Thank you very much for the email and the explaination which is very > > useful. I might have still some problems. It is maybe due to lack of > > enough knowledge in statistics :-) > > I saw that most of the functions return double. Do you mean all > > these are distributed between (0, 1)? Then your solution is in these > > case perfect. But what should I do in the cases where a long int is > > returned? > > I copied and pasted an example from the documents, where an unsined > > int is generated. Almost the same goes for all uniform distributions. > > > > > > Function: unsigned int gsl_ran_poisson (const gsl_rng * r, double > > mu) > > This function returns a random integer from the Poisson distribution > > with mean mu. The probability distribution for Poisson variates is, > > p(k) = {\mu^k \over k!} \exp(-\mu) > > for k >= 0. > > > > Does the above means that the function produces long int values > > between (0, +inf)? > > If so how can I produce (or get) say long ints between (100, 200)? > > Does it make sense even thinking of something between (-100, 150)? > > > > Thanks a lot > > Mohd > > > >> -----Ursprüngliche Nachricht----- > >> Von: "Daniel J Farrell" <[EMAIL PROTECTED]> > >> Gesendet: 17.06.08 18:01:50 > >> An: Mohammad Khaleghi <[EMAIL PROTECTED]> > >> CC: [email protected] > >> Betreff: Re: [Help-gsl] Random numbers within some ranges in the > >> domain using different distributipons? > > > > > >> Hello Mohd, > >> > >> I think you are looking for this function: > >> > >> f(r) = a + (b - a) * r > >> > >> where a is the min value, b is the max values and r is a random > >> number > >> distributed between 0 and 1 (e.g. use gsl_rng_uniform_pos() to > >> generate r). > >> > >> This come up a lot on the mailing list maybe it should be added to > >> the > >> library? > >> > >> Cheers, > >> > >> Dan. > >> > >> > >> > >> On 17 Jun 2008, at 16:26, Mohammad Khaleghi wrote: > >> > >>> Hi everybody! > >>> > >>> Could somebody please tell me how to generate random numbers within > >>> some ranges in the domain? > >>> I saw the documentation and did not see anything like setting a min > >>> and max. I mean for a distribution that has a domain (-inf, + inf) > >>> could one set some range (min, max) to sample from? Or it is not > >>> possible with gsl? > >>> > >>> thans, Mohd > >>> > >>> _______________________________________________________________________ > >>> EINE FÜR ALLE: die kostenlose WEB.DE-Plattform für Freunde und Deine > >>> Homepage mit eigenem Namen. Jetzt starten! http://unddu.de/? > >>> [EMAIL PROTECTED] > >>> > >>> > >>> > >>> _______________________________________________ > >>> Help-gsl mailing list > >>> [email protected] > >>> http://lists.gnu.org/mailman/listinfo/help-gsl > >> > >> > > > > > > ______________________________________________________________ > > Jeden Monat 1 hochkarätiger maxdome-Blockbuster GRATIS! > > Exklusiv für alle WEB.DE Nutzer. http://www.blockbuster.web.de > > > > _______________________________________________________________________ Jetzt neu! Schützen Sie Ihren PC mit McAfee und WEB.DE. 30 Tage kostenlos testen. http://www.pc-sicherheit.web.de/startseite/?mc=022220 _______________________________________________ Help-gsl mailing list [email protected] http://lists.gnu.org/mailman/listinfo/help-gsl
