Re: [Gretl-devel] sorting string arrays

Am 11.04.2019 um 22:20 schrieb Allin Cottrell: > On Thu, 11 Apr 2019, Artur Tarassow wrote: > >> Am 11.04.19 um 18:12 schrieb Sven Schreiber: >>> Am 11.04.2019 um 17:55 schrieb Artur Tarassow: >>>> Just out of curiosity: Gretl wouldn't compute stuff in parallel >>>> out-of-box, right? >>> >>> Hehe, well if "somebody" implemented the cross-array operation natively >>> and used OpenMP or stuff like that then perhaps it would... otherwise: >>> not, I guess. >> >> Of course, I rather meant (without saying it explicitly) whether there >> is some way to exploit C in a simple way to do this. But I guess this >> is rather a non-trivial issue... > > Yes, non-trivial. The thing is, with feval() "anything could happen" > (that is, any part of the libgretl code could be visited as a result of > the function call). Getting this right with OpenMP would require that > libgretl as a whole is thread-safe.

Hm, not sure I understand this point in the given context. What I thought Artur meant is that for a given array of matrices the same operation should be applied to every array member. That sounds to me like a natural parallelization task without race conditions and so on. OK, I guess one has to rule out that the operation itself accesses sister elements in the same array, and I admit that ensuring this may not be trivial. But say you want to apply cdemean() to every matrix in an N-element matrices array. In principle it wouldn't be too difficult to distribute that task to different threads/cores, no?