Question #146882 on DOLFIN changed: https://answers.launchpad.net/dolfin/+question/146882
Anders Logg proposed the following answer: I think you have an old version of DOLFIN. Upgrade to the latest version. Then you can easily compute the gradient by a direct projection (which does the same thing as what Kent suggests): V = VectorFunctionSpace(mesh, "CG", 1) gradu = project(grad(u), V) -- Anders On Fri, Feb 25, 2011 at 07:59:01PM +0100, Kent-Andre Mardal wrote: > The following works fine on my system: > > > from dolfin import * > > mesh = UnitSquare(12,12) > > V = FunctionSpace(mesh, "CG", 1) > scalar1 = Function(V) > > VV = VectorFunctionSpace(mesh, "CG", 1) > u = TrialFunction(VV) > v = TestFunction(VV) > > a = dot(u,v)*dx > L = dot(grad(scalar1), v)*dx > > problem = VariationalProblem(a,L) > c = problem.solve() > > > On 25 February 2011 19:50, JJ Jiang <[email protected]> > wrote: > > Question #146882 on DOLFIN changed: > https://answers.launchpad.net/dolfin/+question/146882 > > JJ Jiang posted a new comment: > Hi Kent, > Thanks for the answer. I used the following script as you suggested. But > the compilation failed. Why? > > VV = VectorFunctionSpace(mesh, "CG", 1) > u = TrialFunction(VV) > v = TestFunction(VV) > > a = dot(u,v)*dx > L = dot(grad(scalar1), v)*dx > > problem = VariationalProblem(a,L) > c = problem.solve() > > Could you please guide me further on that? > > The error message is the following: > In instant.recompile: The module did not compile, see '/tmp/ > tmpCJTm9Y2011-2-25-12-46_instant/ > form_6d04c7c3797b189ed231948384237bf909130ad7/compile.log' > Traceback (most recent call last): > File "demo.py", line 38, in <module> > problem = VariationalProblem(a,L) > File "/usr/local/lib/python2.6/site-packages/dolfin/fem/ > variationalproblem.py", line 40, in __init__ > self.L = Form(L, form_compiler_parameters=form_compiler_parameters) > File "/usr/local/lib/python2.6/site-packages/dolfin/fem/form.py", line > 34, > in __init__ > (self._compiled_form, module, self.form_data) = jit(form, > form_compiler_parameters, common_cell) > File "/usr/local/lib/python2.6/site-packages/dolfin/compilemodules/ > jit.py", line 44, in mpi_jit > return local_jit(*args, **kwargs) > File "/usr/local/lib/python2.6/site-packages/dolfin/compilemodules/ > jit.py", line 103, in jit > return jit_compile(form, parameters=p, common_cell=common_cell) > File "/usr/local/lib/python2.6/dist-packages/ffc/jitcompiler.py", line > 58, > in jit > return jit_form(object, parameters, common_cell) > File "/usr/local/lib/python2.6/dist-packages/ffc/jitcompiler.py", line > 107, in jit_form > cache_dir = cache_dir) > File "/usr/local/lib/python2.6/dist-packages/ufc_utils/build.py", line > 63, > in build_ufc_module > **kwargs) > File "/usr/local/lib/python2.6/dist-packages/instant/build.py", line 474, > in build_module > recompile(modulename, module_path, setup_name, > new_compilation_checksum) > File "/usr/local/lib/python2.6/dist-packages/instant/build.py", line 100, > in recompile > "compile, see '%s'" % compile_log_filename) > File "/usr/local/lib/python2.6/dist-packages/instant/output.py", line 49, > in instant_error > raise RuntimeError(text) > RuntimeError: In instant.recompile: The module did not compile, see '/tmp/ > tmpCJTm9Y2011-2-25-12-46_instant/ > form_6d04c7c3797b189ed231948384237bf909130ad7/compile.log' > > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp > > > _______________________________________________ > Mailing list: https://launchpad.net/~dolfin > Post to : [email protected] > Unsubscribe : https://launchpad.net/~dolfin > More help : https://help.launchpad.net/ListHelp -- You received this question notification because you are a member of DOLFIN Team, which is an answer contact for DOLFIN. _______________________________________________ Mailing list: https://launchpad.net/~dolfin Post to : [email protected] Unsubscribe : https://launchpad.net/~dolfin More help : https://help.launchpad.net/ListHelp
