\subsubsection{The \moc{sybilt} dependent records on a
\moc{GROUP} directory}\label{sect:SYBILgrpdiringdir}

This information is provided only if the current iteration method of the
interface current method is used in SYBIL. This occurs if the key-word {\tt ARM}
is been used in operators {\tt USS:} or {\tt ASM:}. In these cases, the following records will
also be found on the \moc{GROUP} directory:

\vskip 0.2cm

The following dimensions will be used:
\begin{description}

\item[Number of generating cells:] $~$

\begin{displaymath}
\mathcal{N}_{\rm gen} = \left\{
\begin{array}{rll}
\mathcal{P}_1 & \textrm{if~} \mathcal{S}_6^t=3 & \textrm{(do-it-yourself geometry)} \\
\mathcal{P}_6 & \textrm{if~} \mathcal{S}_6^t=4 & \textrm{(2D assembly geometry)}
\end{array} \right.
\end{displaymath}

\item[Number of entering currents in a cell:] $~$

\begin{displaymath}
N_c = \left\{
\begin{array}{rll}
4  & \textrm{if~} \mathcal{P}_1^t=0 \textrm{~and~} 2\le\mathcal{P}_2^t\le 3 & \textrm{($DP_0$ Cartesian cell)} \\
12 & \textrm{if~} \mathcal{P}_1^t=0 \textrm{~and~} \mathcal{P}_2^t=4 &
\textrm{($DP_1$ Cartesian cell)} \\
6  & \textrm{if~} \mathcal{P}_1^t>0 \textrm{~and~} 2\le\mathcal{P}_2^t\le 3 & \textrm{($DP_0$
hexagonal cell)} \\
18 & \textrm{if~} \mathcal{P}_1^t>0 \textrm{~and~} \mathcal{P}_2^t=4 &
\textrm{($DP_1$ hexagonal cell)}
\end{array} \right.
\end{displaymath}

\item[Number of transmission probability elements:] $~$

\begin{displaymath}
D_1 = \left\{
\begin{array}{rll}
\mathcal{P}_1 & \textrm{if~} \mathcal{S}_6^t=3 & \textrm{(do-it-yourself geometry)} \\
\mathcal{P}_6 & \textrm{if~} \mathcal{S}_6^t=4 \textrm{~and~} {\mathcal{P}_2=1} & \textrm{(Roth 2D assembly geometry)} \\
N_c \times N_c \times \mathcal{P}_6 & \textrm{if~} \mathcal{S}_6^t=4 \textrm{~and~}
{\mathcal{P}_2\ge 2} & \textrm{(Other 2D assembly geometries)} \\
\end{array} \right.
\end{displaymath}

\item[Number of escape probability elements:] $~$

\begin{displaymath}
D_2 = \left\{
\begin{array}{rll}
{\tt NMC}(\mathcal{P}_1+1) & \textrm{if~} \mathcal{S}_6^t=3 & \textrm{(do-it-yourself geometry)} \\
{\tt NMC}(\mathcal{P}_6+1) & \textrm{if~} \mathcal{S}_6^t=4 \textrm{~and~} {\mathcal{P}_2=1} & \textrm{(Roth 2D assembly geometry)} \\
N_c \times {\tt NMC}(\mathcal{P}_6+1) & \textrm{if~} \mathcal{S}_6^t=4 \textrm{~and~}
{\mathcal{P}_2\ge 2} & \textrm{(Other 2D assembly geometries)} \\
\end{array} \right.
\end{displaymath}

\item[Number of collision probability elements:] $~$

\begin{displaymath}
D_3 = \sum\limits_{i=1}^{\mathcal{N}_{\rm gen}}[{\tt NMC}(i+1)-{\tt NMC}(i)]^2
\end{displaymath}

\end{description}

\begin{DescriptionEnregistrement}{SYBIL groupwise assembly information in \moc{GROUP}}{7.0cm}
\RealEnr
  {PSSW\$SYBIL\blank{2}}{$\mathcal{D}_1$}{}
  {Cellwise scattering-reduced transmission probabilities.}
\RealEnr
  {PISW\$SYBIL\blank{2}}{$\mathcal{D}_2$}{}
  {Cellwise scattering-reduced escape probabilities.}
\RealEnr
  {PSJW\$SYBIL\blank{2}}{$\mathcal{D}_2$}{}
  {Cellwise scattering-reduced collision probabilities for incoming neutrons.}
\RealEnr
  {PIJW\$SYBIL\blank{2}}{$\mathcal{D}_3$}{}
  {Cellwise scattering-reduced collision probabilities.}
\end{DescriptionEnregistrement}

\eject
