\chapter{{\tt SolveMap}: Forward and Backsolve Map}
\par
The {\tt SolveMap} object is to assign submatrix operations to
threads or processors in a forward and backsolve.
\par
A front is {\it owned} by a single process,
and this ownership is defined by an {\tt owners[]} vector.
If process {\tt myid} owns front {\tt J}, then 
$L_{{\tt J},{\tt J}}$, $D_{{\tt J},{\tt J}}$ and $U_{{\tt J},{\tt J}}$
are owned by {\tt myid}.
The off-diagonal submatrices in the upper block 
and their owners are stored as triples in three vectors.
The {\tt ii}'th submatrix in the upper triangle has 
row id {\tt rowidsUpper[ii]},
column id {\tt colidsUpper[ii]},
and is owned by thread or process {\tt mapUpper[ii]}.
A similar situation holds for the lower triangle when the
factorization is nonsymmetric.
\par
