\subsection{The \moc{snt} dependent records on a \dir{tracking} directory}\label{sect:sntrackingdir}

When the \moc{SNT:} operator is used ($\mathsf{CDOOR}$={\tt 'SN'}), the following elements in the vector
$\mathcal{S}^{t}_{i}$ will also be defined.

\begin{itemize}
\item $\mathcal{S}^{t}_{6}$: ({\tt ITYPE}) Type of SN geometry:
\begin{displaymath}
\mathcal{S}^{t}_{6} = \left\{
\begin{array}{rl}
 2 & \textrm{Cartesian 1-D geometry} \\
 3 & \textrm{Tube 1-D geometry} \\
 4 & \textrm{Spherical 1-D geometry} \\
 5 & \textrm{Cartesian 2-D geometry} \\
 6 & \textrm{Tube 2-D geometry (R-Z geometry)} \\
 7 & \textrm{Cartesian 3-D geometry} \\
 8 & \textrm{Hexagonal 2-D geometry} \\
 9 & \textrm{Hexagonal 3-D geometry}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{7}$: ({\tt NSCT}) Number of spherical harmonics components used to expand the flux and the sources.

%Update to tabular format?
\item $\mathcal{S}^{t}_{8}$: ({\tt IELEM}) Measure of order of the spatial approximation. The Legendre polynomials (for both HODD \emph{and} DG (see $\mathcal{S}^{t}_{10}$)) used are of order 0 (constant), 1 (linear), 2 (parabolic) or 3 (cubic), corresponding to {\tt IELEM} values of:
\begin{displaymath}
\mathcal{S}^{t}_{8} = \left\{
\begin{array}{rl}
 1 & \textrm{Constant (classical diamond scheme) - default for HODD} \\
 2 & \textrm{Linear - default for DG} \\
 3 & \textrm{Parabolic} \\
 4 & \textrm{Cubic (only for DG)}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{9}$: ({\tt NDIM}) Number of geometric dimensions (1, 2 or 3).

\item $\mathcal{S}^{t}_{10}$: ({\tt ISCHM}) Method of spatial discretisation:
\begin{displaymath}
\mathcal{S}^{t}_{10} = \left\{
\begin{array}{rl}
 1 & \textrm{High-Order Diamond Differencing method (HODD) -- default option if unspecified} \\
 2 & \textrm{Discontinuous Galerkin finite element method (DG) -- available if $\mathcal{S}^{t}_{6} = 2, 5,$ or $8$}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{11}$: ({\tt LL4}) Number of mesh-centered flux components in one energy group.
Generally equal to
$\mathcal{S}^{t}_{2}$ except in cases where surfacic fluxes are appended to the
unknown vector. $\mathcal{S}^{t}_{11}\le\mathcal{S}^{t}_{2}$.

\item $\mathcal{S}^{t}_{12}$: ({\tt LX}) Number of elements along the $X$ axis.

\item $\mathcal{S}^{t}_{13}$: ({\tt LY}) Number of elements along the $Y$ axis.

\item $\mathcal{S}^{t}_{14}$: ({\tt LZ}) Number of elements along the $Z$ axis.

\item $\mathcal{S}^{t}_{15}$: ({\tt NLF}) Order of the $S_N$ approximation (even number $\ge 2$).

\item $\mathcal{S}^{t}_{16}$: ({\tt ISCAT}) Number of terms in the scattering sources:
\begin{displaymath}
\mathcal{S}^{t}_{16} = \left\{
\begin{array}{rl}
 1 & \textrm{Isotropic scattering in the laboratory system} \\
 2 & \textrm{Linearly anisotropic scattering in the laboratory system} \\
 n & \textrm{order $n-1$ anisotropic scattering in the laboratory system}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{17}$: ({\tt IQUAD}) Type of angular quadrature:
\begin{displaymath}
\mathcal{S}^{t}_{17} = \left\{
\begin{array}{rl}
 1 & \textrm{Level symmetric, Lathrop and Carlson type} \\
 2 & \textrm{Level symmetric, optimized $\mu_1$ values} \\
 3 & \textrm{Level symmetric, compatible with code SNOW} \\
 4 & \textrm{Legendre-Chebyshev quadrature} \\
 5 & \textrm{symmetric Legendre-Chebyshev quadrature} \\
 6 & \textrm{quadrupole range (QR) quadrature} \\
 10 & \textrm{Gauss-Legendre and Gauss-Chebyshev product quadrature}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{18}$: ({\tt IFIX}) Flag for negative flux fixup:
\begin{displaymath}
\mathcal{S}^{t}_{18} = \left\{
\begin{array}{rl}
 0 & \textrm{Non enabled} \\
 1 & \textrm{Enabled}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{19}$: ({\tt IDSA}) Flag for synthetic diffusion acceleration:
\begin{displaymath}
\mathcal{S}^{t}_{19} = \left\{
\begin{array}{rl}
 0 & \textrm{Non enabled} \\
 1 & \textrm{Enabled}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{20}$: ({\tt NSTART}) Type of acceleration for the scattering iterations:
\begin{displaymath}
\mathcal{S}^{t}_{20} = \left\{
\begin{array}{rl}
 0 & \textrm{GMRES non enabled; use a one-parameter Livolant acceleration} \\
 >0 & \textrm{Restarts the GMRES method every {\tt NSTART} iterations}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{21}$: ({\tt NSDSA}) Number if inner flux iterations {\sl without} DSA in 3-D
cases if $\mathcal{S}^{t}_{8} \ge 2$.

\item $\mathcal{S}^{t}_{22}$: ({\tt MAXI}) Maximum number of inner iterations (resp. maximum number of GMRES(m) iterations if $\mathcal{S}^{t}_{20}>0$).

\item $\mathcal{S}^{t}_{23}$: ({\tt ILIVOL}) Flag for enabling/disabling Livolant acceleration method.
\begin{displaymath}
\mathcal{S}^{t}_{23} = \left\{
\begin{array}{rl}
 0 & \textrm{Non enabled} \\
 1 & \textrm{Enabled}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{24}$: ({\tt icl1}) number of free iterations in the Livolant method.
\item $\mathcal{S}^{t}_{25}$: ({\tt icl2}) number of accelerated iterations in the Livolant method.
\item $\mathcal{S}^{t}_{26}$: ({\tt ISPLH}) Type of hexagonal mesh splitting if $\mathcal{S}^{t}_{6}\ge 8$:
\begin{displaymath}
\mathcal{S}^{t}_{26} = \left\{
\begin{array}{rl}
 1 & \textrm{$3$ lozenges per hexagon} \\
 K & \textrm{$3\times K \times K$ lozenges per hexagon}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{27}$: (INSB) Flux vectorization option where
\begin{displaymath}
\mathcal{S}^{t}_{27} = \left\{
\begin{array}{rl}
 0 & \textrm{Scalar algorithm. The multigroup flux is computed as a sequence of one-group}\\
 & \textrm{solutions using Gauss-Seidel iterations.} \\
 1 & \textrm{Vectorial algorithm. The multigroup flux is computed in parallel for a set of energy}\\
 & \textrm{groups.}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{28}$: (IOMP) Type of OpenMP multithreading strategy in 2D and 3D geometries where
\begin{displaymath}
\mathcal{S}^{t}_{28} = \left\{
\begin{array}{rl}
 0 & \textrm{Standard energy group and discrete angle nested loops}\\
 M & \textrm{Domino type nested loops with $M\times M$ or $M \times M \times M$ macrocells}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{29}$: (IGAV) Type of condition at axial axis for cylindrical and spherical 1D geometries where
\begin{displaymath}
\mathcal{S}^{t}_{29} = \left\{
\begin{array}{rl}
 1 & \textrm{Specular reflection}\\
 2 & \textrm{Zero-weight reflection}\\
 3 & \textrm{Averaged reflection}\\
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{30}$: ({\tt LSHOOT}) Flag for enabling/disabling the shooting method in 1D.
\begin{displaymath}
\mathcal{S}^{t}_{30} = \left\{
\begin{array}{rl}
 0 & \textrm{Non enabled} \\
 1 & \textrm{Enabled}
\end{array} \right.
\end{displaymath}

\item $\mathcal{S}^{t}_{31}$: ({\tt IBFP}) Type of equation solved by the discrete ordinates method.
\begin{displaymath}
\mathcal{S}^{t}_{31} = \left\{
\begin{array}{rl}
 0 & \textrm{Boltzmann transport equation} \\
 1 & \textrm{Boltzmann Fokker-Planck equation with Galarkin energy propagation factors} \\
 2 & \textrm{Boltzmann Fokker-Planck equation with Przybylski and Ligou energy propagation} \\
  & \textrm{factors}
\end{array} \right.
\end{displaymath}
\end{itemize}

The following records will also be present on the main level of a \dir{tracking}
directory.
\begin{DescriptionEnregistrement}{The \moc{snt} records in
\dir{tracking}}{8.0cm}
\IntEnr
  {NCODE\blank{7}}{$6$}
  {Record containing the types of boundary conditions on each surface. =0 side
   not used; =1 VOID; =2 REFL; =4 TRAN. {\tt NOODE(5)} and {\tt NOODE(6)} are not used.} 
\RealEnr
  {ZCODE\blank{7}}{$6$}{$1$}
  {Record containing the albedo value (real number) on each surface. {\tt ZOODE(5)}
   and {\tt ZOODE(6)} are not used.} 
\IntEnr
  {KEYFLX\$ANIS\blank{1}}{$\mathcal{S}^t_1,\mathcal{S}^{t}_{8}**\mathcal{S}^{t}_{9},\mathcal{S}^{t}_{7}$}
  {Location in unknown vector of averaged regional flux moments.} 
\OptDirEnr
  {DSA\blank{9}}{$\mathcal{S}^{t}_{19}= 1$}
  {Sub-directory containing the data related to the diffusion synthetic acceleration using BIVAC (2D) or TRIVAC (3D).
  The specification of this directory is given in \Sect{bivactrackingdir} or in \Sect{trivatrackingdir} } 
\RealEnr
  {EPSI\blank{8}}{$1$}{$1$}
  {Record containing the convergence criterion on inner iterations.}

\end{DescriptionEnregistrement}

If $\mathcal{S}^{t}_{6}=2$ (Cartesian 1-D geometry), the following records will also be present on the main level of a \dir{tracking}
directory.

\begin{DescriptionEnregistrement}{The \moc{snt} records in
\dir{tracking} (Cartesian 1-D geometry)}{8.0cm}
\RealEnr
  {U\blank{11}}{$\mathcal{S}^{t}_{15}$}{$1$}
  {Base points of the angular Gauss-Legendre quadrature.} 
\RealEnr
  {W\blank{11}}{$\mathcal{S}^{t}_{15}$}{$1$}
  {Weights of the angular Gauss-Legendre quadrature.} 
\RealEnr
  {PL\blank{10}}{$\mathcal{S}^{t}_{16},\mathcal{S}^{t}_{15}$}{$1$}
  {Discrete values of the Legendre polynomials on the quadrature base points.} 
\end{DescriptionEnregistrement}
\clearpage

If $\mathcal{S}^{t}_{6}=3$ (Tube 1-D geometry), the following records will also be present on the main level of a \dir{tracking}
directory. The number of discrete directions in two octants $N_{\rm angl}$ and the number of spherical harmonics components of the flux $N_{\rm pn}$
are given in term of the $S_N$ order $N=\mathcal{S}^{t}_{15}$ as
$$
N_{\rm angl}=\cases{{\displaystyle 1\over \displaystyle 2}N\left(1+{\displaystyle N\over \displaystyle 2}\right),
&if $\mathcal{S}^{t}_{17}<10$;\cr {\displaystyle 1\over \displaystyle 2}N^2, &otherwise. \cr}
$$
$$
N_{\rm pn}={\mathcal{S}^{t}_{16}\over 2}\left( 1+{\mathcal{S}^{t}_{16}\over 2}\right)+
{1\over 2} (1+\mathcal{S}^{t}_{16})\, (\mathcal{S}^{t}_{16}{\rm mod} \, 2)
$$

\begin{DescriptionEnregistrement}{The \moc{snt} records in
\dir{tracking} (tube 1-D geometry)}{8.0cm}
\IntEnr
  {JOP\blank{9}}{$N/2$}
  {Number of base points in each $\xi$ level.} 
\RealEnr
  {U\blank{11}}{$N/2$}{$1$}
  {Base points (levels) of the angular quadrature in $\xi$ (positive values).} 
\RealEnr
  {UPQ\blank{9}}{$N_{\rm angl}$}{$1$}
  {Direction cosines of the angular two-octants spherical harmonics quadrature in $\mu$.} 
\RealEnr
  {WPQ\blank{9}}{$N_{\rm angl}$}{$1$}
  {Weights of the angular two-octants spherical harmonics quadrature.} 
\RealEnr
  {ALPHA\blank{7}}{$N_{\rm angl}$}{$1$}
  {Angular redistribution parameters.} 
\RealEnr
  {PLZ\blank{9}}{$N_{\rm pn},N/2$}{$1$}
  {Discrete values of the real spherical harmonics on the zero-weight base points.} 
\RealEnr
  {PL\blank{10}}{$N_{\rm pn},N_{\rm angl}$}{$1$}
  {Discrete values of the real spherical harmonics on the quadrature base points.} 
\RealEnr
  {SURF\blank{8}}{$\mathcal{S}^{t}_{12}+1$}{$1$}
  {Surfaces.} 
\end{DescriptionEnregistrement}

If $\mathcal{S}^{t}_{6}=4$ (Spherical 1-D geometry), the following records will also be present on the main level of a \dir{tracking}
directory.

\begin{DescriptionEnregistrement}{The \moc{snt} records in
\dir{tracking} (spherical 1-D geometry)}{8.0cm}
\RealEnr
  {U\blank{11}}{$\mathcal{S}^{t}_{15}$}{$1$}
  {Base points of the angular Gauss-Legendre quadrature.} 
\RealEnr
  {W\blank{11}}{$\mathcal{S}^{t}_{15}$}{$1$}
  {Weights of the angular Gauss-Legendre quadrature.} 
\RealEnr
  {ALPHA\blank{7}}{$\mathcal{S}^{t}_{15}$}{$1$}
  {Angular redistribution parameters.} 
\RealEnr
  {PLZ\blank{9}}{$\mathcal{S}^{t}_{16}$}{$1$}
  {Discrete values of the Legendre polynomials on the zero-weight base points at $\mu=-1$.} 
\RealEnr
  {PL\blank{10}}{$\mathcal{S}^{t}_{16},\mathcal{S}^{t}_{15}$}{$1$}
  {Discrete values of the Legendre polynomials on the quadrature base points.} 
\RealEnr
  {SURF\blank{8}}{$\mathcal{S}^{t}_{12}+1$}{$1$}
  {Surfaces.} 
\RealEnr
  {XXX\blank{9}}{$\mathcal{S}^{t}_{12}+1$}{$1$}
  {Mesh-edge radii.} 
\end{DescriptionEnregistrement}

If $\mathcal{S}^{t}_{6}=5$ (Cartesian 2-D geometry) or $\mathcal{S}^{t}_{6}=6$ (R-Z geometry), the following records will also be present on the main level of a \dir{tracking}
directory. The number of discrete directions in four octants (including zero-weight points) $N_{\rm angl}$ and the number of spherical harmonics components of the flux $N_{\rm pn}$
are given in term of the $S_N$ order $N=\mathcal{S}^{t}_{15}$ as
$$
N_{\rm angl}={1\over 2}(N+4)N
$$
$$
N_{\rm pn}={\mathcal{S}^{t}_{16}\over 2}\left( 1+\mathcal{S}^{t}_{16}\right)
$$

\begin{DescriptionEnregistrement}{The \moc{snt} records in
\dir{tracking} (Cartesian 2-D and R-Z geometries)}{8.0cm}
\RealEnr
  {DU\blank{10}}{$N_{\rm angl}$}{$1$}
  {Direction cosines of the angular four-octants spherical harmonics quadrature in $\mu$.} 
\RealEnr
  {DE\blank{10}}{$N_{\rm angl}$}{$1$}
  {Direction cosines of the angular four-octants spherical harmonics quadrature in $\eta$.} 
\RealEnr
  {W\blank{11}}{$N_{\rm angl}$}{$1$}
  {Weights of the angular four-octants spherical harmonics quadrature.} 
\IntEnr
  {MRM\blank{9}}{$N_{\rm angl}$}
  {Quadrature offsets.} 
\IntEnr
  {MRMY\blank{8}}{$N_{\rm angl}$}
  {Quadrature offsets.} 
\RealEnr
  {DB\blank{10}}{$\mathcal{S}^{t}_{12},N_{\rm angl}$}{$1$}
  {Diamond-scheme parameter.} 
\RealEnr
  {DA\blank{10}}{$\mathcal{S}^{t}_{12},\mathcal{S}^{t}_{13},N_{\rm angl}$}{$1$}
  {Diamond-scheme parameter.} 
\OptRealEnr
  {DAL\blank{9}}{$\mathcal{S}^{t}_{12},\mathcal{S}^{t}_{13},N_{\rm angl}$}{$\mathcal{S}^{t}_{6}=6$}{$1$}
  {Angular redistribution parameters.} 
\RealEnr
  {PL\blank{10}}{$N_{\rm pn},N_{\rm angl}$}{$1$}
  {Discrete values of the real spherical harmonics on the quadrature base points.} 
\end{DescriptionEnregistrement}

If $\mathcal{S}^{t}_{6}=7$ (Cartesian 3-D geometry), the following records will also be present on the main level of a \dir{tracking}
directory. The number of discrete directions in height octants  $N_{\rm angl}$ and the number of spherical harmonics components of the flux $N_{\rm pn}$
are given in term of the $S_N$ order $N=\mathcal{S}^{t}_{15}$ as
$$
N_{\rm angl}=(N+2)N
$$
$$
N_{\rm pn}=\left( 1+\mathcal{S}^{t}_{16}\right)^{2}
$$

\begin{DescriptionEnregistrement}{The \moc{snt} records in
\dir{tracking} (Cartesian 3-D geometry)}{8.0cm}
\RealEnr
  {DU\blank{10}}{$N_{\rm angl}$}{$1$}
  {Direction cosines of the angular height-octants spherical harmonics quadrature in $\mu$.} 
\RealEnr
  {DE\blank{10}}{$N_{\rm angl}$}{$1$}
  {Direction cosines of the angular height-octants spherical harmonics quadrature in $\eta$.} 
\RealEnr
  {DZ\blank{10}}{$N_{\rm angl}$}{$1$}
  {Direction cosines of the angular height-octants spherical harmonics quadrature in $\xi$.} 
\RealEnr
  {W\blank{11}}{$N_{\rm angl}$}{$1$}
  {Weights of the angular height-octants spherical harmonics quadrature.} 
\IntEnr
  {MRMX\blank{9}}{$N_{\rm angl}$}
  {Quadrature offsets.} 
\IntEnr
  {MRMY\blank{8}}{$N_{\rm angl}$}
  {Quadrature offsets.} 
\IntEnr
  {MRMZ\blank{8}}{$N_{\rm angl}$}
  {Quadrature offsets.} 
\RealEnr
  {DC\blank{10}}{$\mathcal{S}^{t}_{12},\mathcal{S}^{t}_{13},N_{\rm angl}$}{$1$}
  {Diamond-scheme parameter.} 
\RealEnr
  {DB\blank{10}}{$\mathcal{S}^{t}_{12},\mathcal{S}^{t}_{14},N_{\rm angl}$}{$1$}
  {Diamond-scheme parameter.} 
\RealEnr
  {DA\blank{10}}{$\mathcal{S}^{t}_{13},\mathcal{S}^{t}_{14},N_{\rm angl}$}{$1$}
  {Diamond-scheme parameter.} 
\RealEnr
  {PL\blank{10}}{$N_{\rm pn},N_{\rm angl}$}{$1$}
  {Discrete values of the real spherical harmonics on the quadrature base points.} 
\end{DescriptionEnregistrement}

\eject
