My DEC (Discrete Exterior Calculus) implementation which now marginally works. To some degree this was an experiment in how much I could stretch C++ to allow myself to write code "mathematically".

##Documentation I've started a doxygen for the source code, but it still needs quite a lot of work (I haven't seriously started commenting the code yet) http://www.dgp.toronto.edu/~mtao/dec-doc

##Requirements

• gcc4.7 or clang3.1 (or some compiler with decent c++11 support)
• cmake
• Eigen, which should be 3.1 but might require the development branch

• This implements the core features required in a DEC implementation such as definitions for the discrete exterior derivative and the hodge star.
• Compiles really really slowly due to all of the type deduction I require the compiler to deal with.
• The simplicial complex (nesh) representation follows an is-a relationship fairly strictly in that simplicial complexes of n dimensions inherit from simplicial complexes of m dimensions, for all m < n.
• Typechecking for differential forms and operators.
• Can compose differential operators using the syntax

to create an expression template that sits ontop of Eigen's expresison template system. This is all done through the above mentioned typechecking and a template deduction.