QCaml/Basis/Overlap.ml

112 lines
3.5 KiB
OCaml

open Util
(** Computes all the overlap integrals of the contracted shell pair *)
let contracted_class shell_a shell_b : float Zmap.t =
let shell_p =
Shell_pair.create_array shell_a shell_b
in
(* Pre-computation of integral class indices *)
let class_indices =
Angular_momentum.zkey_array (Angular_momentum.Doublet
Contracted_shell.(totAngMom shell_a, totAngMom shell_b))
in
let contracted_class =
Array.make (Array.length class_indices) 0.
in
(* Compute all integrals in the shell for each pair of significant shell pairs *)
for ab=0 to (Array.length shell_p - 1)
do
let coef_prod =
shell_p.(ab).Shell_pair.coef
in
(** Screening on thr product of coefficients *)
if (abs_float coef_prod) > 1.e-4*.cutoff then
begin
let center_ab =
shell_p.(ab).Shell_pair.center_ab
in
let center_a =
shell_p.(ab).Shell_pair.center_a
in
let expo_inv =
shell_p.(ab).Shell_pair.expo_inv
in
Array.iteri (fun i key ->
let (angMomA,angMomB) =
let a = Zkey.to_int_array Zkey.Kind_6 key in
( [| a.(0) ; a.(1) ; a.(2) |],
[| a.(3) ; a.(4) ; a.(5) |] )
in
let norm =
shell_p.(ab).Shell_pair.norm_fun angMomA angMomB
in
let f k =
Overlap_primitives.hvrr (angMomA.(k), angMomB.(k))
expo_inv
(Coordinate.coord center_ab k,
Coordinate.coord center_a k)
in
let integral = chop norm (fun () -> (f 0)*.(f 1)*.(f 2)) in
contracted_class.(i) <- contracted_class.(i) +. coef_prod *. integral
) class_indices
end
done;
let result =
Zmap.create (Array.length contracted_class)
in
Array.iteri (fun i key -> Zmap.add result key contracted_class.(i)) class_indices;
result
(** Write all overlap integrals to a file *)
let to_file ~filename basis =
let to_int_tuple x =
let open Zkey in
match to_int_tuple Kind_3 x with
| Three x -> x
| _ -> assert false
in
let oc = open_out filename in
for i=0 to (Array.length basis) - 1 do
print_int basis.(i).Contracted_shell.indice ; print_newline ();
for j=0 to i do
(* Compute all the integrals of the class *)
let cls =
contracted_class basis.(i) basis.(j)
in
(* Write the data in the output file *)
Array.iteri (fun i_c powers_i ->
let i_c = basis.(i).Contracted_shell.indice + i_c + 1 in
let xi = to_int_tuple powers_i in
Array.iteri (fun j_c powers_j ->
let j_c = basis.(j).Contracted_shell.indice + j_c + 1 in
let xj = to_int_tuple powers_j in
let key =
Zkey.of_int_tuple (Zkey.Six (xi,xj))
in
let value =
try
Zmap.find cls key
with Not_found -> failwith "Bug in overlap integrals"
in
if (abs_float value > cutoff) then
Printf.fprintf oc "%4d %4d %20.12e\n"
i_c j_c value
) basis.(j).Contracted_shell.powers
) basis.(i).Contracted_shell.powers;
done;
done;
close_out oc