open Common type t = { contracted_shell_pairs : Contracted_shell_pair.t list; atomic_shell_a : Atomic_shell.t; atomic_shell_b : Atomic_shell.t; } module Am = Angular_momentum module As = Atomic_shell module Co = Coordinate module Cs = Contracted_shell module Csp = Contracted_shell_pair (** Creates an atomic shell pair : an array of pairs of contracted shells. *) let make ?(cutoff=Constants.epsilon) atomic_shell_a atomic_shell_b = let l_a = Array.to_list (As.contracted_shells atomic_shell_a) and l_b = Array.to_list (As.contracted_shells atomic_shell_b) in let contracted_shell_pairs = List.concat_map (fun s_a -> List.map (fun s_b -> if Cs.index s_b <= Cs.index s_a then Csp.make ~cutoff s_a s_b else None ) l_b ) l_a |> Util.list_some in match contracted_shell_pairs with | [] -> None | _ -> Some { atomic_shell_a ; atomic_shell_b ; contracted_shell_pairs } let atomic_shell_a x = x.atomic_shell_a let atomic_shell_b x = x.atomic_shell_b let contracted_shell_pairs x = x.contracted_shell_pairs let monocentric x = Csp.monocentric @@ List.hd x.contracted_shell_pairs let a_minus_b x = Csp.a_minus_b @@ List.hd x.contracted_shell_pairs let a_minus_b_sq x = Csp.a_minus_b_sq @@ List.hd x.contracted_shell_pairs let ang_mom x = Csp.ang_mom @@ List.hd x.contracted_shell_pairs let norm_scales x = Csp.norm_scales @@ List.hd x.contracted_shell_pairs (** The array of all shell pairs with their correspondance in the list of contracted shells. *) let of_atomic_shell_array ?(cutoff=Constants.epsilon) basis = Array.mapi (fun i shell_a -> Array.map (fun shell_b -> make ~cutoff shell_a shell_b) (Array.sub basis 0 (i+1)) ) basis