\section{Input}
There are three fundamental inputs to the program:
\begin{enumerate}
\item Model of the guide field. The model is described in the {\it BMAD} style as 'lattice' files. 
The lattice file consists of standard 'elements' (dipole magnets, quadrupole magnets, drifts, etc.),
'custom' elements (backleg fringe, inflector, pulsed kicker), and 'markers' with special functions like
colimators, detector planes, etc. The elements, characterized by a length, a curvature and a function, 
are arranged in a 'line' that fixes the geometry. The 'lattice' file
is parsed by the {\it BMAD} subroutine 'bmad\_parser' and the data is loaded into fortran structures for easy access. An example of a
lattice file that is appropriate for tracking particles from the end of the M5 line, through backleg and inflector
and into the ring is 
\href{http://www.classe.cornell.edu/~dlr/g-2/bmad\_tracking\_code/g-2/files/bmad\_esquad\_grid.}{\tt bmad\_esquad\_grid.}
\item Run specific inputs, (lattice file to read, number of particles to track, number of turns around the ring, initial
distribution, initial offsets, peak kicker field, kicker pulse shape, quad field index, etc.) are set in a namelist file
'input.dat', for example, \href{http://www.classe.cornell.edu/~dlr/g-2/bmad\_tracking\_code/g-2/files/input.dat}{\tt input.dat}
\item Reference data files. Reference files include magnetic and electric field maps, kicker pulse shape, 
initial muon distributions, temporal distributions of injected muon pulses, alternative representations of lattice 
elements, etc. Linux style 'soft links' provide access to reference data files. The current complete set of soft links 
effective on the Cornell grid is
\href{http://www.classe.cornell.edu/~dlr/g-2/bmad\_tracking\_code/g-2/softlink\_lnx}{\tt softlink\_lnx}
\end{enumerate}
