On 8 March 2012 12:36, Johan Hake <hake....@gmail.com> wrote: > On Thu, Mar 8, 2012 at 12:40 PM, Garth N. Wells <gn...@cam.ac.uk> wrote: >> The obvious first step to simplifying dolfin:Array is to minimise its >> use. Any objections to changing dolfin::Array to std::vector in the >> GenericFoo abstract linear algebra classes? > > It is only GenericVector that uses Array at the moment. Are you > thinking of changing all double* to std::vector too? > >> The consequence on the Python side will be copying of data. I don't >> think that this is an issue since the interfaces are low-level and >> only likely used from Python for prototyping or debugging. In such >> cases, I would expect that other aspects of the Python overhead to >> swamp to cost of the data copy. > > Where it makes sense I am inclined to keep the Array class, and even > if get,set are low level functionalities they are something that > potentially will be called many times.
Will they ever be called many times from Python in production code? They will be called from low-level C++ code, but using std::vector will make no difference in this case since it will be passed by reference. > I do not have a benchmark > telling you that it makes a difference, but from my perspective it > doesn't make sense to change to std::vector just for the sake of it. > The point is to simplify dolfin::Array. The most important usage is in GenericFunction::eval, in which case it has fixed length. It was the usage of dolfin::Array in this context that Joachim picked up the performance issue. I favour dolfin::Array being as simple as possible and targeted to handle the call-back type situation in GenericFunction::eval both efficiently and safely (from both Python and C++). Garth > Johan > >> Garth >> >> _______________________________________________ >> Mailing list: https://launchpad.net/~dolfin >> Post to : dolfin@lists.launchpad.net >> Unsubscribe : https://launchpad.net/~dolfin >> More help : https://help.launchpad.net/ListHelp -- Garth N. Wells Department of Engineering, University of Cambridge http://www.eng.cam.ac.uk/~gnw20 _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
