QCaml/Basis/NucInt.ml

130 lines
3.5 KiB
OCaml

(** Electron-nucleus repulsion integrals *)
open Util
open Constants
open Bigarray
(** (0|0)^m : Fundamental electron-nucleus repulsion integral
$ \int \phi_p(r1) 1/r_{C} dr_1 $
maxm : Maximum total angular momentum
expo_pq_inv : $1./p + 1./q$ where $p$ and $q$ are the exponents of
$\phi_p$ and $\phi_q$
norm_pq_sq : square of the distance between the centers of $\phi_p$
and $\phi_q$
*)
let zero_m ~maxm ~expo_pq_inv ~norm_pq_sq =
let exp_pq = 1. /. expo_pq_inv in
let t = norm_pq_sq *. exp_pq in
boys_function ~maxm t
|> Array.mapi (fun m fm ->
two_over_sq_pi *. fm *.
(pow exp_pq m) *. (sqrt exp_pq)
)
(** Compute all the integrals of a contracted class *)
let contracted_class_shell_pair shell_p geometry: float Zmap.t =
OneElectronRR.contracted_class_shell_pair ~zero_m shell_p geometry
let cutoff2 = cutoff *. cutoff
exception NullIntegral
(*
(** Unique index for integral <ij|kl> *)
let index i j k l =
let f i k =
let (p,r) =
if i <= k then (i,k) else (k,i)
in p+ (r*r-r)/2
in
let p = f i k and q = f j l in
f p q
*)
(** Write all integrals to a file with the <ij|kl> convention *)
let to_file ~filename basis geometry =
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
(* Pre-compute all shell pairs *)
let shell_pairs =
Array.mapi (fun i shell_a -> Array.map (fun shell_b ->
Shell_pair.create_array shell_a shell_b) (Array.sub basis 0 (i+1)) ) basis
in
Printf.printf "%d shells\n" (Array.length basis);
let eni_array =
let n = ref 0 in
for i=0 to (Array.length basis) - 1 do
n := !n + (Array.length (basis.(i).Contracted_shell.powers))
done;
let n = !n in
Array2.create Float64 c_layout n n
in
Array2.fill eni_array 0.;
(* Compute Integrals *)
let t0 = Unix.gettimeofday () in
let inn = ref 0 and out = ref 0 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
let
shell_p = shell_pairs.(i).(j)
in
(* Compute all the integrals of the class *)
let cls =
contracted_class_shell_pair shell_p geometry
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 =
Zmap.find cls key
in
if (abs_float value > cutoff) then
(inn := !inn + 1;
eni_array.{(i_c-1),(j_c-1)} <- value;
)
else
out := !out + 1;
) basis.(j).Contracted_shell.powers
) basis.(i).Contracted_shell.powers;
done;
done;
Printf.printf "Computed %d non-zero ENIs in %f seconds\n" !inn (Unix.gettimeofday () -. t0);
(* Print ENIs *)
for i_c=1 to (Array2.dim1 eni_array) do
for j_c=1 to (Array2.dim2 eni_array) do
let value = eni_array.{(i_c-1),(j_c-1)} in
if (value <> 0.) then
Printf.fprintf oc " %5d %5d%20.15f\n" i_c j_c value;
done;
done;
Printf.printf "In: %d Out:%d\n" !inn !out ;
close_out oc