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diff --git a/doc/IGE335/Section3.04_trivac.tex b/doc/IGE335/Section3.04_trivac.tex new file mode 100644 index 0000000..0324f8f --- /dev/null +++ b/doc/IGE335/Section3.04_trivac.tex @@ -0,0 +1,135 @@ +\subsubsection{The {\tt TRIVAT:} tracking module}\label{sect:TRIVACData} + +The {\tt TRIVAT:} module provides an implementation of the diffusion or simplified $P_n$ method. The {\tt TRIVAT:} module is +used to perform a TRIVAC-type ``tracking" on a 1D/2D/3D regular Cartesian or hexagonal geometry.\cite{BIVAC,TRIVAC} The +geometry is analyzed and a LCM object with signature {\tt L\_TRIVAC} is created with the following information: + +\begin{itemize} +\item Diagonal and hexagonal symmetries are unfolded and the mesh-splitting +operations are performed. Volumes, material mixture and averaged flux recovery +indices are computed on the resulting geometry. \item A finite element +discretization is performed and the corresponding numbering is saved. \item The +unit finite element matrices (mass, stiffness, etc.) are recovered. \item +Indices related to an ADI preconditioning with or without supervectorization +are saved. \end{itemize} + +The calling specification for this module is: + +\begin{DataStructure}{Structure \dstr{TRIVAT:}} +\dusa{TRKNAM} +\moc{:=} \moc{TRIVAT:} $[$ \dusa{TRKNAM} $]$ +\dusa{GEONAM} \moc{::} \dstr{desctrack} \dstr{descTRIVAC} +\end{DataStructure} + +\noindent where +\begin{ListeDeDescription}{mmmmmmm} + +\item[\dusa{TRKNAM}] {\tt character*12} name of the \dds{tracking} data +structure that will contain region volume and surface area vectors in +addition to region identification pointers and other tracking information. +If \dusa{TRKNAM} also appears on the RHS, the previous tracking +parameters will be applied by default on the current geometry. + +\item[\dusa{GEONAM}] {\tt character*12} name of the \dds{geometry} data +structure. + +\item[\dstr{desctrack}] structure describing the general tracking data (see +\Sect{TRKData}) + +\item[\dstr{descTRIVAC}] structure describing the transport tracking data +specific to \moc{TRIVAT:}. + +\end{ListeDeDescription} + +\vskip 0.2cm + +The \moc{TRIVAT:} specific tracking data in \dstr{descTRIVAC} is defined as + +\begin{DataStructure}{Structure \dstr{descTRIVAC}} +$[~\{$ \moc{PRIM} $[$ \dusa{ielem} $]~|$ \moc{DUAL} $[$ \dusa{ielem} \dusa{icol} $]~|$ \moc{MCFD} $[$ \dusa{ielem} $]~|$ \moc{LUMP} $[$ \dusa{ielem} $]~\}~]$ \\ +$[$ \moc{SPN} $[$ \moc{DIFF} $]$ \dusa{nlf} $[$ \moc{SCAT} \dusa{iscat} $]~[$ \moc{VOID} \dusa{nvd} $]~]$ \\ +$[$ \moc{ADI} \dusa{nadi} $]$ \\ +$[$ \moc{VECT} $[$ \dusa{iseg} $]~[$ \moc{PRTV} \dusa{impv} $]~]$ \\ +{\tt ;} +\end{DataStructure} + +\noindent where +\begin{ListeDeDescription}{mmmmmm} + +\item[\dstr{desctrack}] structure describing the general tracking data (see +\Sect{TRKData}) + +\item[\moc{PRIM}] key word to set a discretization based on the variational collocation method. + +\item[\moc{DUAL}] key word to set a mixed-dual finite element discretization. If the +geometry is hexagonal, a Thomas-Raviart-Schneider method is used. + +\item[\moc{MCFD}] key word to set a discretization based on the nodal +collocation method. The mesh centered finite difference approximation is the +default option and is generally set using {\tt MCFD~1}. The {\tt MCFD} +approximations are numerically equivalent to the {\tt DUAL} approximations +with \dusa{icol}=2; however, the {\tt MCFD} approximations are less +expensive. + +\item[\moc{LUMP}] key word to set a discretization based on the nodal +collocation method with serendipity approximation. The serendipity +approximation is different from the \moc{MCFD} option in cases with \dusa{ielem}$\ge$2. This option is not available for hexagonal geometries. + +\item[\dusa{ielem}] order of the finite element representation. The values +permitted are: 1 (linear polynomials), 2 (parabolic polynomials), 3 (cubic +polynomials) or 4 (quartic polynomials). By default \dusa{ielem}=1. + +\item[\dusa{icol}] type of quadrature used to integrate the mass matrices. +The values permitted are: 1 (analytical integration), 2 (Gauss-Lobatto +quadrature) or 3 (Gauss-Legendre quadrature). By default \dusa{icol}=2. The +analytical integration corresponds to classical finite elements; the +Gauss-Lobatto quadrature corresponds to a variational or nodal type +collocation and the Gauss-Legendre quadrature corresponds to superconvergent +finite elements. + +\item[\moc{SPN}] keyword to set a simplified spherical harmonics ($SP_n$) expansion +of the flux.\cite{nse2005,ane10a} This option is available with 1D, 2D and 3D Cartesian geometries and with 2D and 3D +hexagonal geometries. + +\item[\moc{DIFF}] keyword to force using $1/3D^{g}$ as $\Sigma_1^{g}-\Sigma_{{\rm s}1}^{g}$ cross sections. A $P_1$ or $SP_1$ method +will therefore behave as diffusion theory. + +\item[\dusa{nlf}] order of the $P_n$ or $SP_n$ expansion (odd number). Set to zero for diffusion theory (default value). + +\item[\moc{SCAT}] keyword to limit the anisotropy of scattering sources. + +\item[\dusa{iscat}] number of terms in the scattering sources. \dusa{iscat} $=1$ is used for +isotropic scattering in the laboratory system. \dusa{iscat} $=2$ is used for +linearly anisotropic scattering in the laboratory system. The default value is set to $n+1$ +in $P_n$ or $SP_n$ case. + +\item[\moc{VOID}] key word to set the number of base points in the Gauss-Legendre quadrature used to integrate +void boundary conditions if \dusa{icol} $=3$ and \dusa{n} $\ne 0$. + +\item[\dusa{nvd}] type of quadrature. The values +permitted are: 0 (use a (\dusa{n}$+2$)--point quadrature consistent with $P_{\rm n}$ theory), +1 (use a (\dusa{n}$+1$)--point quadrature consistent with $S_{{\rm n}+1}$ theory), +2 (use an analytical integration of the void boundary conditions). By default \dusa{nvd}=0. + +\item[\moc{ADI}] keyword to set the number of ADI iterations at the inner +iterative level. + +\item[\dusa{nadi}] number of ADI iterations (default: \dusa{nadi} $=2$). + +\item[\moc{VECT}] key word to set an ADI preconditionning with +supervectorization. By default, TRIVAC uses an ADI preconditionning without +supervectorization. + +\item[\dusa{iseg}] width of a vectorial register. \dusa{iseg} is generally a multiple of 64. By default, \dusa{iseg}=64. + +\item[\moc{PRTV}] key word used to set \dusa{impv}. + +\item[\dusa{impv}] index used to control the printing in supervectorization +subroutines. =0 for no print; =1 for minimum printing (default value); Larger +values produce increasing amounts of output. + +\end{ListeDeDescription} + +Various finite element approximations can be obtained with different values of \dusa{ielem}. + +\eject |
