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Fem-fenics: Difference between revisions
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Added Known issues section to report problems discussed on the mailing list
(Added Known issues section to report problems discussed on the mailing list) |
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*The '''coefficient of the variational problem''' can be specified using either an ''Expression()'', a ''Constant()'' or a ''Function()''. They are different objects which behave in different ways: an ''Expession'' or a ''Constant'' object overloads the eval() method of the dolfin::Expression class and it is evaluated at run time using the octave function feval (). A ''Function'' instead doesn't need to be evaluated because it is assembled copying element-by-element the values contained in the input vector. | *The '''coefficient of the variational problem''' can be specified using either an ''Expression()'', a ''Constant()'' or a ''Function()''. They are different objects which behave in different ways: an ''Expession'' or a ''Constant'' object overloads the eval() method of the dolfin::Expression class and it is evaluated at run time using the octave function feval (). A ''Function'' instead doesn't need to be evaluated because it is assembled copying element-by-element the values contained in the input vector. | ||
== Known issues == | |||
* Fem-fenics needs both in the installation phase and in normal usage some includes that are not in standard system include directories, namely those related to MPI and the Eigen template library. If you experience an installation failure or errors when importing your UFL files, then you should properly set your CPPFLAGS environment variable before launching Octave, as per [http://octave.1599824.n4.nabble.com/fem-fenics-0-0-1-released-tp4662182p4662195.html]. This can be done in {{Path|sh}} compatible shells with the command below: | |||
<syntaxhighlight lang="bash" style="font-size:13px"> | |||
export CPPFLAGS="-I/usr/include/eigen3 $(mpicxx -showme:compile)" | |||
</syntaxhighlight> | |||
It should readily work in Ubuntu 13.10, notice that {{Path|/usr/include/eigen3}} has to be changed accordingly to the path in which Eigen are to be found on your system. | |||
* There is a known bug with Openmpi, discussed on the maintainers list [http://octave.1599824.n4.nabble.com/fem-fenics-0-0-1-released-tp4662182p4662234.html], that needs the preloading of a MPI shared library with the following command: | |||
<syntaxhighlight lang="bash" style="font-size:13px"> | |||
export LD_PRELOAD=/usr/lib/openmpi/lib/libmpi.so | |||
</syntaxhighlight> | |||
Again, notice that {{Path|/usr/lib/openmpi/lib/libmpi.so}} has to be changed to fit to your system. | |||
== Additional functionality / TODOS == | == Additional functionality / TODOS == | ||