Abstract de la publi numéro 7210
We describe a fill-reducing ordering algorithm
for sparse, nonsymmetric LU factorizations, where the pivots are
restricted to the diagonal and are selected greedily.
The ordering algorithm only uses the structural information.
Most of the existing methods are based on some
type of symmetrization of the original matrix.
Our algorithm exploits the nonsymmetric structure
of the given matrix as much as possible. The new algorithm is
thus more complex than classical symmetric orderings but we show that our
algorithm can be implemented in space bounded by the number of
nonzero entries in the original matrix, and has the same
time complexity as the analogous algorithms for symmetric matrices.
We provide numerical experiments to demonstrate the ordering quality
and the runtime of the new ordering algorithm.