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104 lines
3.0 KiB
OCaml
104 lines
3.0 KiB
OCaml
(* [[file:~/QCaml/perturbation/mp2.org::*Type][Type:2]] *)
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type t = {
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energy : float ;
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mo_basis : Mo.Basis.t ;
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frozen_core : Mo.Frozen_core.t ;
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}
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(* Type:2 ends here *)
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(* | ~make~ | Creates an MP2 data structure |
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*
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* #+begin_example
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* let mp2 =
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* Perturbation.Mp2.make ~frozen_core:(Mo.Frozen_core.(make Small nuclei)) mo_basis
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* ;;
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* val mp2 : Perturbation.Mp2.t = E(MP2)=-0.185523
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* #+end_example *)
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(* [[file:~/QCaml/perturbation/mp2.org::*Creation][Creation:2]] *)
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open Linear_algebra
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let make_rmp2 mo_basis mo_class =
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let epsilon = Mo.Basis.mo_energies mo_basis in
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let eri = Mo.Basis.ee_ints mo_basis in
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let inactives =
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List.filter (fun i ->
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match i with Mo.Class.Inactive _ -> true | _ -> false) mo_class
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and virtuals =
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List.filter (fun i ->
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match i with Mo.Class.Virtual _ -> true | _ -> false) mo_class
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in
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List.fold_left (fun accu b ->
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match b with Mo.Class.Virtual b ->
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let eps = -. (epsilon%.(b)) in
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accu +.
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List.fold_left (fun accu a ->
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match a with Mo.Class.Virtual a ->
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let eps = eps -. (epsilon%.(a)) in
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accu +.
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List.fold_left (fun accu j ->
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match j with Mo.Class.Inactive j ->
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let eps = eps +. epsilon%.(j) in
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accu +.
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List.fold_left (fun accu i ->
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match i with Mo.Class.Inactive i ->
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let eps = eps +. epsilon%.(i) in
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let ijab = Four_idx_storage.get_phys eri i j a b
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and abji = Four_idx_storage.get_phys eri a b j i in
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let abij = ijab in
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accu +. ijab *. ( abij +. abij -. abji) /. eps
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| _ -> accu
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) 0. inactives
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| _ -> accu
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) 0. inactives
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| _ -> accu
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) 0. virtuals
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| _ -> accu
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) 0. virtuals
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let make ~frozen_core mo_basis =
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let mo_class =
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Mo.Class.cas_sd mo_basis ~frozen_core 0 0
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|> Mo.Class.to_list
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in
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let energy =
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match Mo.Basis.mo_type mo_basis with
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| RHF -> make_rmp2 mo_basis mo_class
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| ROHF -> Common.Util.not_implemented "ROHF MP2"
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| UHF -> Common.Util.not_implemented "UHF MP2"
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| _ -> invalid_arg "MP2 needs RHF or ROHF MOs"
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in
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{ energy ; mo_basis ; frozen_core }
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(* Creation:2 ends here *)
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(* | ~energy~ | Returns the MP2 energy |
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* | ~mo_basis~ | Returns the MO basis on which the MP2 energy was computed |
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* | ~frozen_core~ | Returns the frozen_core scheme used to compute the MP2 energy |
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*
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* #+begin_example
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*
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* #+end_example *)
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(* [[file:~/QCaml/perturbation/mp2.org::*Access][Access:2]] *)
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let energy t = t.energy
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let mo_basis t = t.mo_basis
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let frozen_core t = t.frozen_core
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(* Access:2 ends here *)
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(* [[file:~/QCaml/perturbation/mp2.org::*Printers][Printers:2]] *)
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let pp ppf t =
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Format.fprintf ppf "@[E(MP2)=%f@]" t.energy
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(* Printers:2 ends here *)
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