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QCaml/linear_algebra/lib/four_idx_storage.mli

80 lines
2.6 KiB
OCaml

(** Storage for four-index data (integrals, density matrices, ...).
There are two kinds of ordering of indices:
- Physicist's : {% $\langle i j | k l \rangle$ %}
- Chemist's : {% $(ij|kl)$ %}
*)
type 'a t
(** Element for the stream *)
type element =
{
i_r1: int ;
j_r2: int ;
k_r1: int ;
l_r2: int ;
value: float
}
val create : size:int -> [< `Dense | `Sparse ] -> 'a t
(** If [`Dense] is chosen, internally the data is stored as a 4-dimensional
[Bigarray]. Else, it is stored as a hash table.
*)
(** {2 Accessors} *)
val size : 'a t -> int
(** Number of stored elements *)
val get_chem : 'a t -> int -> int -> int -> int -> float
(** Get an integral using the Chemist's convention {% $(ij|kl)$ %}. *)
val get_phys : 'a t -> int -> int -> int -> int -> float
(** Get an integral using the Physicist's convention {% $\langle ij|kl \rangle$ %}. *)
val set_chem : 'a t -> int -> int -> int -> int -> float -> unit
(** Set an integral using the Chemist's convention {% $(ij|kl)$ %}. *)
val set_phys : 'a t -> int -> int -> int -> int -> float -> unit
(** Set an integral using the Physicist's convention {% $\langle ij|kl \rangle$ %}. *)
val increment_chem : 'a t -> int -> int -> int -> int -> float -> unit
(** Increments an integral using the Chemist's convention {% $(ij|kl)$ %}. *)
val increment_phys : 'a t -> int -> int -> int -> int -> float -> unit
(** Increments an integral using the Physicist's convention {% $\langle ij|kl \rangle$ %}. *)
val get_chem_all_i : 'a t -> j:int -> k:int -> l:int -> 'a Vector.t
(** Get all integrals in an array [a.{i} =] {% $(\cdot j|kl)$ %} . *)
val get_phys_all_i : 'a t -> j:int -> k:int -> l:int -> 'a Vector.t
(** Get all integrals in an array [a.{i} =] {% $\langle \cdot j|kl \rangle$ %} . *)
val get_chem_all_ij : 'a t -> k:int -> l:int -> ('a,'a) Matrix.t
(** Get all integrals in an array [a.{i,j} =] {% $(\cdot \cdot|kl)$ %} . *)
val get_phys_all_ij : 'a t -> k:int -> l:int -> ('a,'a) Matrix.t
(** Get all integrals in an array [a.{i,j} =] {% $\langle \cdot \cdot|kl \rangle$ %} . *)
val to_stream : 'a t -> element Stream.t
(** Retrun the data structure as a stream. *)
val to_list : 'a t -> element list
(** Retrun the data structure as a list. *)
val four_index_transform : ('a,'b) Matrix.t -> 'a t -> 'b t
(** Perform a four-index transformation *)
(** {2 I/O} *)
val to_file : ?cutoff:float -> filename:string -> 'a t -> unit
(** Write the data to file, using the physicist's ordering. *)
val of_file : size:int -> sparsity:[< `Dense | `Sparse ]
-> Scanf.Scanning.file_name -> 'a t
(** Read from a text file with format ["%d %d %d %d %f"]. *)