Multigrid for propagators of staggered fermions in four-dimensional $SU(2)$ gauge fields

Multigrid (MG) methods for the computation of propagators of staggered fermions in non-Abelian gauge fields are discussed. MG could work in principle in arbitrarily disordered systems. The practical variational MG methods tested so far with a ``Laplacian choice’’ for the restriction operator are not competitive with the conjugate gradient algorithm on lattices up to ${18}^4$. Numerical results are presented for propagators in $SU(2)$ gauge fields.