Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ILU Smoothers for C-AMG with Scaled Triangular Factors   ILU smoothers can be effective in the algebraic multigrid $V$-cycle. However,
direct triangular solves are comparatively slow on GPUs. Previous work by Chow
and Patel \cite{ChowPatel2015} and Antz et al. \cite{Anzt2015} proposed an
iterative approach to solve these systems. Unfortunately, when the Jacobi
iteration is applied to highly non-normal upper or lower triangular factors,
the iterations will diverge. An ILU smoother is introduced for classical
Ruge-St\"uben C-AMG that applies row and/or column scaling to mitigate the
non-normality of the upper triangular factor. Our approach facilitates the use
of Jacobi iteration in place of the inherently sequential triangular solve.
Because the scaling is applied to the upper triangular factor, it can be done
locally for a diagonal block of the global matrix. An ILUT Schur complement
smoother, that solves the Schur system along subdomain (MPI rank) boundaries
using GMRES, maintains a constant iteration count and improves strong-scaling.
Numerical results and parallel performance are presented for the Nalu-Wind and
PeleLM \cite{PeleLM} pressure solvers. For large problem sizes, GMRES$+$AMG
with iterative triangular solves executes at least five times faster than when
using direct solves on the NREL Eagle supercomputer.

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The categories of this paper are: bayes-an
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The categories of this paper are: nlin
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: acc-phys
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The categories of this paper are: physics
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The categories of this paper are: plasm-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: quant-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: econ
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The categories of this paper are: alg-geom
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The categories of this paper are: cond-mat
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The categories of this paper are: ao-sci
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The categories of this paper are: nucl-th
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The categories of this paper are: funct-an