Test_staggered_hdcg.cc implements a two-level ADEF2 multigrid solver for
NaiveStaggeredFermion using SchurStaggeredOperator, following the mrhs
hermitian multigrid approach of arXiv:2409.03904. Uses a 33-point coarse
stencil (NextToNearestStencilGeometry4D) with nbasis=24, block={4,4,4,4},
and Chebyshev subspace generation with hi=5.0 (lambda_max ~4.6).
Also adds systems/mac-arm/sourceme-homebrew.sh and config-command-homebrew
for building Grid on Apple Silicon with Homebrew-installed dependencies.
Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>
Thomas Blum