pub fn lanczos_ritz<O>(
operator: &O,
initial: &[Complex64],
options: LanczosOptions,
) -> Result<LanczosRitzDecomposition>where
O: LinearOperator + ?Sized,Expand description
Full Lanczos basis plus the sorted eigensystem of its tridiagonal projection. This is the reusable native object behind compatibility interfaces which expose both Ritz data and later reconstruction.