Hi, I have spotted a performance problem after I have upgraded from 1.15 to 1.16.
When I use odeiv2 to obtain numerical solutions from simulations, I found that the program gets significantly slowed down by more than 10 times. After a brief investigation, I found that it should be caused by the amendment by Tuomo Keskitalo (see http://bzr.savannah.gnu.org/lh/gsl/trunk/revision/4771). In which, he proposed that copying from dydt_out to dydt_in can save cpu time. However, I think, in many situations, memcpy is not a good choice. To test my guess, I have tried to undo his amendment to see if it is the cause. I found that the performance becomes the same as before after my modification. Running time: 1.16 (original): 2m12s 1.16 (modified): 12s compiler: gcc4.8.1 os: kubuntu 13.10 I am not the only guy who have this performance problem (see http://comments.gmane.org/gmane.comp.lib.gsl.general/4418). I guess Keskitalo's idea may be beneficial for some projects, but not all. I would like to propose that, the revision 4771 should be undone. Thanks for your attention. Alan
