|Bill Allombert on Mon, 17 Sep 2012 22:58:14 +0200|
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On Mon, Sep 17, 2012 at 10:21:03PM +0200, Karim Belabas wrote: > * Bill Allombert [2012-09-17 18:50]: > > I feel concerned because I will have to write dedicated code for GP2C to > > handle it... > > How much dedicated code ? I intended to add a few more loop constructs to GP: > > - forstepprime() [ loop over primes in an arithmetic progression ] > - forprimepowers() [ loop over prime powers ] > > How costly would these be ? (The first one is already in master, only not > exported to GP yet.) > > Those are (much) more useful than forcomposite(), although I thought it didn't > hurt to have the latter. Since it's non-trivial to write properly... There are basically two way to do it: either libpari provides forcomposite_init/forcomposite_next or GP2C inlines the code of forcomposite using forprime_init/forprime_next for each usage of forcomposite. Both of them require a significant amount of coding. It is still hard to imagine an application of forcomposite() where performances matter. Cheers, Bill.