  The reproducibility of experiments is one of the main principles of the
scientific method. However, numerical N-body experiments, especially those of
planetary systems, are currently not reproducible. In the most optimistic
scenario, they can only be replicated in an approximate or statistical sense.
Even if authors share their full source code and initial conditions,
differences in compilers, libraries, operating systems or hardware often lead
to qualitatively different results.
  We provide a new set of easy-to-use, open-source tools that address the above
issues, allowing for exact (bit-by-bit) reproducibility of N-body experiments.
In addition to generating completely reproducible integrations, we show that
our framework also offers novel and innovative ways to analyze these
simulations. As an example, we present a high-accuracy integration of the Solar
System spanning 10Gyrs, requiring several weeks to run on a modern CPU. In our
framework we can not only easily access simulation data at predefined intervals
for which we save snapshots, but at any time during the integration. We achieve
this by integrating an on-demand reconstructed simulation forward in time from
the nearest snapshot. This allows us to extract arbitrary quantities at any
point in the saved simulation exactly (bit-by-bit), and within seconds rather
than weeks.
  We believe that the tools we present in this paper offer a new paradigm for
how N-body simulations are run, analyzed, and shared across the community.
