LOBPCG method descriptor.

Usage

lobpcg(maxit = NULL, preconditioner = NULL, constraints = NULL)

Arguments

maxit: Maximum LOBPCG iterations. NULL (default) uses the solve's maxit argument when given, else the eigencore.lobpcg_maxit option (200). Supplying both this and a different solve-level maxit is an error.
preconditioner: Optional function taking a residual block and returning a preconditioned block with the same dimensions.
constraints: Optional matrix whose columns span a subspace to deflate. Iterates are kept orthogonal to this subspace in the Euclidean or generalized B inner product. Native constrained LOBPCG is not promoted yet; constrained problems use the labelled reference path.

Value

An eigencore_method descriptor selecting LOBPCG. Built-in standard Hermitian dense/CSC operators may use a native prototype; unsupported cases route to the reference prototype.