* At lower level, a few general purpose libraries in Python and C++, e.g. :

  * A new C++ multi-dimensional array library (triqs::arrays).
  * A simple dictionary-like python :ref:`interface to HDF5 files<hdf5_base>`, which is the main data format in TRIQS.
  * A thin :ref:`interface to matplotlib<plotting>` to visualize various objects via the definition of a :ref:`plot protocol<plotting>`.