Automatic solver choice.

Usage

auto(max_subspace = NULL)

max_subspace: Optional maximum Krylov subspace size (the ARPACK ncv). When the planner selects a restarted Krylov route (thick-restart or block Lanczos, Krylov-Schur Arnoldi, shift-invert Lanczos or Arnoldi, Golub-Kahan, or implicit-Gram Lanczos for SVD) this caps the active basis; it is capped at the problem dimension and must leave room for the wanted pairs (at least k + 1, k + block for block Lanczos). Routes without a Krylov basis (dense LAPACK, explicit Gram SVD, LOBPCG) ignore it. NULL (default) uses the route's own default. The solve's maxit argument is the iteration (restart) limit and never changes the subspace size.

An eigencore_method descriptor that lets the planner choose a solver based on problem structure.