On 22 November 2011 21:58, Anders Logg <l...@simula.no> wrote: > On Tue, Nov 22, 2011 at 09:53:47PM +0000, Garth N. Wells wrote: >> On 22 November 2011 21:50, Anders Logg <l...@simula.no> wrote: >> > On Tue, Nov 22, 2011 at 09:33:25PM +0000, Garth N. Wells wrote: >> >> On 22 November 2011 21:30, Anders Logg <l...@simula.no> wrote: >> >> > On Tue, Nov 22, 2011 at 10:16:54PM +0100, Marie E. Rognes wrote: >> >> >> On 11/22/2011 09:55 PM, Anders Logg wrote: >> >> >> >On Tue, Nov 22, 2011 at 08:45:30PM +0000, Garth N. Wells wrote: >> >> >> >> >> >> >> >>On 21 Nov 2011, at 21:53, "Marie E. Rognes"<m...@simula.no> wrote: >> >> >> >> >> >> >> >>> >> >> >> >>>On 21. nov. 2011, at 21:52, Anders Logg<l...@simula.no> wrote: >> >> >> >>> >> >> >> >>>>On Mon, Nov 21, 2011 at 08:46:13PM +0000, Garth N. Wells wrote: >> >> >> >>>>>On 21 November 2011 13:07, Anders Logg<l...@simula.no> wrote: >> >> >> >>>>>>On Sun, Nov 20, 2011 at 11:55:43PM +0100, Anders Logg wrote: >> >> >> >>>>>>>On Sun, Nov 20, 2011 at 11:49:42PM +0100, Marie E. Rognes wrote: >> >> >> >>>>>>>> >> >> >> >>>>>>>>On 20. nov. 2011, at 23:31, Anders Logg<l...@simula.no> wrote: >> >> >> >>>>>>>> >> >> >> >>>>>>>>>Is anyone using the Function constructor that takes a vector >> >> >> >>>>>>>>>as input >> >> >> >>>>>>>>>argument? >> >> >> >>>>>>>>> >> >> >> >>>>>>>>>Function u(V, x); >> >> >> >>>>>>>>> >> >> >> >>>>>>>>Yes. >> >> >> >>>>>>>Does it work? In parallel? >> >> >> >>>>>>> >> >> >> >>>>>>>Does it not work to instead use >> >> >> >>>>>>> >> >> >> >>>>>>> x = u.vector() >> >> >> >>>>>>> >> >> >> >>>>>>>? >> >> >> >>>>>>> >> >> >> >>>>>>>If you need it, we should keep it but add an error message that >> >> >> >>>>>>>it >> >> >> >>>>>>>doesn't work in parallel, unless it does... >> >> >> >>>>>>Any more input on this? There are several options: >> >> >> >>>>>> >> >> >> >>>>>>1. Remove this constructor >> >> >> >>>>>> >> >> >> >>>>>>2. Throw an error when running in parallel >> >> >> >>>>>> >> >> >> >>>>>>3. Check that the input vector makes sense >> >> >> >>>>>> >> >> >> >>>>>>The last one is problematic since I don't see an easy way to >> >> >> >>>>>>perform >> >> >> >>>>>>the check, other than calling get_local and having it fail. >> >> >> >>>>>> >> >> >> >>>>>I haven't heard any reason why it can't be removed. We may need >> >> >> >>>>>to fix >> >> >> >>>>>assignment (re earlier discussion on assign) to just copy values >> >> >> >>>>>and >> >> >> >>>>>not the whole object so that a user can get the vector and then >> >> >> >>>>>assign >> >> >> >>>>>values to it without messing up the ghosting. >> >> >> >>>>Sounds good, but I want to wait for Marie to comment before I >> >> >> >>>>remove >> >> >> >>>>it. She is using it. >> >> >> >>>> >> >> >> >>>>Marie? Does it work for you to use x = u.vector()? >> >> >> >>>> >> >> >> >>>Probably. However removing the constructor would be changing parts >> >> >> >>>of the basic interface, which I think is a bad idea. >> >> >> >>> >> >> >> >>>Add a warning if you want to deprecate it later. >> >> >> >>> >> >> >> >>Isn't the time to make an interface change now rather than later? >> >> >> >> >> >> I would say that the time to make an interface change before >> >> >> 1.0 has passed: I see more value in sticking to >> >> >> to what we have claimed, than in fixing this single instance. >> >> >> >> >> >> >True, but last time we discussed this was 1 hour or so before the >> >> >> >release of 1.0-rc1. Now we have a whole week to 1.0-rc2... :-) >> >> >> > >> >> >> >Marie, can you check again if that constructor is necessary? >> >> >> >> >> >> I'm typically using it for the same as the dolfin la/eigenvalue demo >> >> >> is using it for. >> >> >> Do you have a replacement syntax available? >> > >> > Marie, I think this should work: >> > >> > u = Function(V) >> > u.vector()[:] = x >> > >> > where x is the solution you get from the eigenvalue problem. >> > >> > Can you see if that works? >> > >> >> It won't, because of a bad flaw in the vector assignment. It will >> make u.vector()[:] a copy of x (which has the wrong parallel layout) , >> when what we want is to assign just the values. > > I thought you argued before that was the correct behavior? (When we > discussed the subfunction assignment last week.) >
I argued that it is being done consistently, but not that it's right. We need to distinguish between copying and object and assigning just values of a vector (but not touching the layout, ghost values, etc) to another vector of the same length. > Is it much work to fix that before 1.0-rc2? > Proper assignment is too much work. I'm adding a work-around fix now so the eigenvalue demo should be correct in parallel. Garth > -- > Anders > > >> Garth >> >> > >> > >> > >> >> >> That said, I'm not going to lose any sleep over this. >> >> > >> >> > Is everyone ok with throwing an error that it doesn't work in >> >> > parallel? >> >> > >> >> >> >> I don't think that is ideal. >> >> >> >> I building now with the constructors commented out to see how many >> >> changes would be required. >> > >> > > _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
