2009/2/24 Anders Logg <[email protected]>: > On Tue, Feb 24, 2009 at 08:07:43PM +0000, A Navaei wrote: >> 2009/2/24 Johan Hake <[email protected]>: >> > On Tuesday 24 February 2009 16:17:43 A Navaei wrote: >> >> 2009/2/24 Johan Hake <[email protected]>: >> >> > On Tuesday 24 February 2009 01:08:11 A Navaei wrote: >> >> >> Finally after all those long discussions on the best way of >> >> >> architecturing variational image processing problems based on dolfin, >> >> >> a minimal demo showing how to solve a classical motion estimation PDE >> >> >> is available now -- thanks for all the support. Detailed explanation >> >> >> is given here: >> >> >> >> >> >> http://code.google.com/p/debiosee/wiki/DemosOptiocFlowHornSchunck >> >> >> >> >> >> Currently, the c++ implementation is done and the python wrapper is on >> >> >> the way. >> >> > >> >> > Cool! >> >> > >> >> >> I have tried to perform sub-classing as much as possible and leave the >> >> >> rest to be implemented outside of the main classes. While this works, >> >> >> there is a tiny problem which I'm not quite happy about. Here is >> >> >> what's happening: >> >> >> >> >> >> [ITK-backend] >> >> >> >> >> >> v >> >> >> [GenericImage]-------\ >> >> >> >> >> >> v | >> >> >> [ImageToMesh] | >> >> >> >> >> >> v | >> >> >> [FunctionSpace] | >> >> >> >> >> >> v | >> >> >> [ImageFunction]<-----/ >> >> >> >> >> >> If you still cannot see what's happening, get a monospace font :) What >> >> >> I don't like is the right branch connecting GenericImage to >> >> >> ImageFunction. There should be a way of making sure that the two >> >> >> branches are initiated from the same image source, or this could be a >> >> >> source of error. Simply encapsulating this in a class takes away the >> >> >> freedom of defining a general problem away from the user. >> >> > >> >> > Just a thought: >> >> > >> >> > Would it help to let GenericImage also be a dolfin::Mesh? Then in >> >> > ITKImage you copy paste the algorithm for creating a >> >> > UnitCube/UnitSquare/Rectange/Box (the algorithms are actually not very >> >> > large). >> >> >> >> I understand that implemented algorithms are short, but maybe it's not >> >> a good practice to copy/paste the code (even if it's a short code). We >> >> should think of a more creative way of doing this. >> > >> > Sure ;) >> > >> > One alternative could be to inherit UnitSquare directly but then we need to >> > put the creation algorithm in, e.g., an init function (protected such ;) ). >> > This will then be called in the constructor, and we also need an empty >> > constructor to be called by the inherited mesh, which may or may not make >> > any >> > sense at all. >> >> This looks like something feasible to me. What about having a virtual >> Mesh::Init() called in Mesh() so that the subclasses just have to >> override Init()? Then in the ImageMesh case, the parent Init() should >> be also called and the extra branch in the diagram will disappear. > > It doesn't seem to be a good idea to make the construction of the mesh > optional in subclasses of UnitSquare. Generally, we try to avoid > init() functions (as we've had plenty of them before and it > complicates the design). > > It would be better to do something like this: > > class ImageMesh : public Mesh > { > public: > > ImageMesh(const Image& image) : Mesh() > { > // Compute nx, ny etc > > // Create unit square mesh and copy it > UnitSquare mesh(nx, ny); > *this = mesh; > } > > };
I did try this before creating ImageToMesh. I guess it needs the right copy constructor as I get this error: error: no match for ‘operator=’ in ‘*(debiosee::ImageMesh*)this = mesh’ then, creating the copy constructor seems unnecessary since we have to copy everything that the subclass owns. I also tried downcasting using dynamic_cast, but it didn't work. -ALi > >> In case you missed the other question, is the information about number >> of cells in each dimension lost in UnitSquare or can it be retrieved? > > It's lost but it could easily be added. > > -- > Anders > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.9 (GNU/Linux) > > iEYEARECAAYFAkmkVyMACgkQTuwUCDsYZdGMjgCbBgrxY0jPbC/WB+UNa2WSKsZo > wt0An0s3W7VkxUSPFaeyojflKqkFTJRd > =ZJ1s > -----END PGP SIGNATURE----- > > _______________________________________________ > DOLFIN-dev mailing list > [email protected] > http://www.fenics.org/mailman/listinfo/dolfin-dev > > _______________________________________________ DOLFIN-dev mailing list [email protected] http://www.fenics.org/mailman/listinfo/dolfin-dev
