On Wednesday 10 March 2010 05:39:21 Chris Richardson wrote: > New question #103867 on DOLFIN: > https://answers.launchpad.net/dolfin/+question/103867 > > I have a mesh generator, written in C++, which I have now linked with > dolfin, using the MeshEditor class to construct a mesh. This works, but I > would like to be able to use it from python.
Cool! Do you link your generator to any particular triangulation/tetrahedarlization library? I have written one TriTetMesh which wrap Triangle and Tetgen. It is a bit sharp in the edges, but perfectly usable both from C++ and Python. Have a look at: <https://launchpad.net/tritetmesh> You should also be able to get some clues of how you can do the linking to PyDOLFIN using TriTetMesh, as I also use SWIG. I do not return a mesh during runtime, I just saves it to file. It spare me for some nasty SWIG related stuff, which I eventually could fix. > I have tried to use SWIG to > create a module, but I don't know how to tell it that my new class > inherits Mesh. You need to %import the types. PyDOLFIN comes with some handy SWIG import files, if you just want to import the types related to Mesh. You should for example be able to put: %include "dolfin/swig/import/mesh.i" before your SWIG declarations. This file %import's all the types from the dolfin/mesh kernel modules, which is probably what you want. If you want to return a mesh at runtime you might experience some nasty surprises as Mesh is a shared_ptr stored type in PyDOLFIN. This means you need to explicitly tell SWIG this. Please ask for more help if you want to do this. We also have a JIT compiler of DOLFIN code in PyDOLFIN, which (should) automagicaly take care of the shared_ptr declarations. compile_extension_module(code, module_name="", recompile=False, dolfin_module_import=None, additional_declarations="", additional_system_headers=None, use_numpy_typemaps=True) This function is unfortunately wrapped by a Python decorator (due to some parallel fixes), so the interactive documentation is None. Here comes a summary: code is a 'str' with your C++ code. module_name is an optional name for your module, dolfin_module_import is a list of 'str' with name of the kernel module, in you case 'mesh', the other arguments can be used to fine tune typemaps. Take a look in site-packages/dolfin/compile_modules/__init__.py where the function is defined and in site-packages/dolfin/compile_modules/{subdomains.py, expression.py} where the function is used. The answer might be more than you asked for, but I would really like to have users of the compile_extension_module function ;) Best regards, Johan > Here is a summary of my code... but maybe there is a better way to do this? > > Chris > > mymesh.i > ======== > > %module mymesh > %{ > /* Put header files here or function declarations like below */ > #include "mymesh.h" > %} Put %import/%include statement here. > /* mymesh.h */ > namespace dolfin{ > > class Mymesh : public Mesh > { > public: > Mymesh(); > }; > } > > mymesh.cpp > ========== > > #include "mymesh.h" > > #include <dolfin/mesh/MeshPartitioning.h> > #include <dolfin/mesh/MeshEditor.h> > #include <dolfin.h> > > using namespace dolfin; > ..... > Mymesh::Mymesh() { > Mesheditor editor; > .... > } > > > # swig -c++ -python mymesh.i > mymesh.i:11: Warning(401): Nothing known about base class 'Mesh'. Ignored. > _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
