On 25 November 2011 12:56, Anders Logg <l...@simula.no> wrote: > Looks like you need to check that you are not running in parallel in > that test since DOLFIN will otherwise try to partition the mesh which > doesn't work if you only have one cell.
Done. Kristian > -- > Anders > > > On Fri, Nov 25, 2011 at 10:58:17AM +0100, Kristian Ølgaard wrote: >> On 24 November 2011 20:33, Anders Logg <l...@simula.no> wrote: >> > On Thu, Nov 24, 2011 at 01:43:20PM +0100, Kristian Ølgaard wrote: >> >> On 23 November 2011 10:54, Martin Sandve Alnæs <marti...@simula.no> wrote: >> >> > On 23 November 2011 09:37, Kristian Ølgaard <k.b.oelga...@gmail.com> >> >> > wrote: >> >> >> On 22 November 2011 21:15, Kristian Ølgaard <k.b.oelga...@gmail.com> >> >> >> wrote: >> >> >>> On 22 November 2011 21:07, Anders Logg <l...@simula.no> wrote: >> >> >>>> On Tue, Nov 22, 2011 at 07:34:38PM +0000, Garth N. Wells wrote: >> >> >>>>> On 22 November 2011 19:12, Kristian Ølgaard >> >> >>>>> <k.b.oelga...@gmail.com> wrote: >> >> >>>>> > Hi, >> >> >>>>> > >> >> >>>>> > The IntervalCell::facet_area in DOLFIN currently returns 0.0, >> >> >>>>> > while >> >> >>>>> > the facet determinant (a scale factor) 'det = 1.0;' >> >> >>>>> > in the generated code for the tabulate_tensor function in 1D >> >> >>>>> > (facet integrals). >> >> >>>>> > >> >> >>>>> > Is 0.0 the correct return value, or should it return 1.0? >> >> >>>>> > >> >> >>>>> >> >> >>>>> I would think 1.0. >> >> >>> >> >> >>> That's what I'm leaning towards too. >> >> >>> >> >> >>>> Facet is the thing of dimension one lower than the cell dimension so >> >> >>>> in this case 1 - 1 so it would mean the area of an endpoint. So I >> >> >>>> believe 0 is correct. >> >> >>> >> >> >>> I see your 'point' :), but is it consistent with how we evaluate >> >> >>> integrals on endpoints? >> >> >> >> >> >> Running this script: >> >> >> >> >> >> from dolfin import * >> >> >> >> >> >> cells = [interval, triangle, tetrahedron] >> >> >> meshes = [UnitInterval(1), UnitSquare(1,1), UnitCube(1,1,1)] >> >> >> >> >> >> for cell, mesh in zip(cells, meshes): >> >> > >> >> > btw, you can do >> >> > cell = mesh.ufl_cell() >> >> > >> >> >> c = Constant(1, cell) >> >> >> print >> >> >> print cell >> >> >> print "volume: ", assemble(c*dx, mesh=mesh) >> >> >> print "surface: ", assemble(c*ds, mesh=mesh) >> >> >> >> >> >> produces: >> >> >> >> >> >> <interval cell in R1> >> >> >> volume: 1.0 >> >> >> surface: 2.0 >> >> >> >> >> >> <triangle cell in R2> >> >> >> volume: 1.0 >> >> >> surface: 4.0 >> >> >> >> >> >> <tetrahedron cell in R3> >> >> >> volume: 1.0 >> >> >> surface: 6.0 >> >> >> >> >> >> If we want surface = 0.0 for the interval, 'det' must be set to zero >> >> >> in the generated code. >> >> >> However, doing so will mean that f*ds etc. becomes zero too, which is >> >> >> not very useful. >> >> >> >> >> >> Kristian >> >> > >> >> > As Kristian shows here, I think defining it to 1.0 seems more useful, >> >> > and consistent with the definition of 1.0*ds. >> >> >> >> I've pushed the change to DOLFIN, the output of the extended script: >> >> >> >> from dolfin import * >> >> >> >> for mesh in [UnitInterval(1), UnitSquare(1,1), UnitCube(1,1,1)]: >> >> c = Constant(1, mesh.ufl_cell()) >> >> c0 = mesh.ufl_cell().facet_area >> >> c1 = FacetArea(mesh) >> >> print >> >> print mesh.ufl_cell() >> >> print "volume: ", assemble(c*dx, mesh=mesh) >> >> print "surface: ", assemble(c*ds, mesh=mesh) >> >> print "facet_area ufl/ffc: ", assemble(c0*ds, mesh=mesh) >> >> print "FacetArea dolfin: ", assemble(c1*ds, mesh=mesh) >> >> >> >> is >> >> >> >> <interval cell in R1> >> >> volume: 1.0 >> >> surface: 2.0 >> >> facet_area ufl/ffc: 2.0 >> >> FacetArea dolfin: 2.0 >> >> >> >> <triangle cell in R2> >> >> volume: 1.0 >> >> surface: 4.0 >> >> facet_area ufl/ffc: 4.0 >> >> FacetArea dolfin: 4.0 >> >> >> >> <tetrahedron cell in R3> >> >> volume: 1.0 >> >> surface: 6.0 >> >> facet_area ufl/ffc: 3.0 >> >> FacetArea dolfin: 3.0 >> >> >> >> Kristian >> > >> > ok. >> > >> > Can you make it into a unit test? (Maybe you already did, I haven't >> > checked.) >> >> I put the above script in >> test/unit/function/python/SpecialFunctions.py (not pushed to repo) >> >> but doing >> >> mpirun -np 3 python ./SpecialFunctions.py >> >> results in the error: >> >> Process 0: Number of global vertices: 2 >> Process 0: Number of global cells: 1 >> EE >> ====================================================================== >> ERROR: testFacetArea (__main__.SpecialFunctions) >> ---------------------------------------------------------------------- >> Traceback (most recent call last): >> File "./SpecialFunctions.py", line 29, in testFacetArea >> references = [(UnitInterval(1), 2, 2),]#\ >> File >> "/home/oelgaard/software/fenics/lib/python2.7/site-packages/dolfin/cpp.py", >> line 12959, in __init__ >> _cpp.UnitInterval_swiginit(self,_cpp.new_UnitInterval(*args)) >> RuntimeError: >> >> *** ------------------------------------------------------------------------- >> *** DOLFIN encountered an error. If you are not able to resolve this issue >> *** using the information listed below, you can ask for help at >> *** >> *** https://answers.launchpad.net/dolfin >> *** >> *** Remember to include the error message listed below and, if possible, >> *** include a *minimal* running example to reproduce the error. >> *** >> *** ------------------------------------------------------------------------- >> *** Error: Unable to compute mesh partitioning using ParMETIS. >> *** Reason: ParMETIS cannot be used if a process has no cells (graph >> nodes). Use SCOTCH to perform partitioning instead. >> *** Where: This error was encountered inside ParMETIS.cpp. >> *** ------------------------------------------------------------------------- >> >> >> ---------------------------------------------------------------------- >> Ran 1 test in 0.003s >> >> FAILED (errors=1) >> >> ====================================================================== >> ERROR: testFacetArea (__main__.SpecialFunctions) >> ---------------------------------------------------------------------- >> Traceback (most recent call last): >> File "./SpecialFunctions.py", line 29, in testFacetArea >> references = [(UnitInterval(1), 2, 2),]#\ >> File >> "/home/oelgaard/software/fenics/lib/python2.7/site-packages/dolfin/cpp.py", >> line 12959, in __init__ >> _cpp.UnitInterval_swiginit(self,_cpp.new_UnitInterval(*args)) >> RuntimeError: >> >> *** ------------------------------------------------------------------------- >> *** DOLFIN encountered an error. If you are not able to resolve this issue >> *** using the information listed below, you can ask for help at >> *** >> *** https://answers.launchpad.net/dolfin >> *** >> *** Remember to include the error message listed below and, if possible, >> *** include a *minimal* running example to reproduce the error. >> *** >> *** ------------------------------------------------------------------------- >> *** Error: Unable to compute mesh partitioning using ParMETIS. >> *** Reason: ParMETIS cannot be used if a process has no cells (graph >> nodes). Use SCOTCH to perform partitioning instead. >> *** Where: This error was encountered inside ParMETIS.cpp. >> *** ------------------------------------------------------------------------- >> >> >> ---------------------------------------------------------------------- >> Ran 1 test in 0.003s >> >> FAILED (errors=1) >> >> >> after which the process hangs. >> >> Kristian >> >> > > _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : dolfin@lists.launchpad.net Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
