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QCaml/common/lib/coordinate.ml
2022-11-07 14:59:11 +01:00

152 lines
3.5 KiB
OCaml

(* [[file:~/QCaml/common/coordinate.org::*Type][Type:2]] *)
type bohr
type angstrom
type xyz = {
x : float ;
y : float ;
z : float ;
}
type 'a point = xyz
type t = bohr point
type axis = X | Y | Z
(* Type:2 ends here *)
(* | ~make~ | Creates a point in atomic units |
* | ~make_angstrom~ | Creates a point in angstrom |
* | ~zero~ | $(0., 0., 0.)$ | *)
(* [[file:~/QCaml/common/coordinate.org::*Creation][Creation:2]] *)
external make : 'a point -> t = "%identity"
external make_angstrom : 'a point -> angstrom point = "%identity"
let zero =
make { x = 0. ; y = 0. ; z = 0. }
(* Creation:2 ends here *)
(* | ~bohr_to_angstrom~ | Converts a point in bohr to angstrom |
* | ~angstrom_to_bohr~ | Converts a point in angstrom to bohr | *)
(* [[file:~/QCaml/common/coordinate.org::*Conversion][Conversion:2]] *)
let b_to_a b = Constants.a0 *. b
let bohr_to_angstrom { x ; y ; z } =
make { x = b_to_a x ;
y = b_to_a y ;
z = b_to_a z ; }
let a_to_b a = Constants.a0_inv *. a
let angstrom_to_bohr { x ; y ; z } =
make { x = a_to_b x ;
y = a_to_b y ;
z = a_to_b z ; }
(* Conversion:2 ends here *)
(* | ~neg~ | Negative of a point |
* | ~get~ | Extracts the projection of the coordinate on an axis |
* | ~dot~ | Dot product |
* | ~norm~ | $\ell{^2}$ norm of the vector |
* | $\vert .$ | Scales the vector by a constant |
* | $\vert +$ | Adds two vectors |
* | $\vert -$ | Subtracts two vectors |
*
* Example:
* #+begin_example
* Coordinate.neg { x=1. ; y=2. ; z=3. } ;;
* - : Coordinate.t = -1.0000 -2.0000 -3.0000
*
* Coordinate.(get Y { x=1. ; y=2. ; z=3. }) ;;
* - : float = 2.
*
* Coordinate.(
* 2. |. { x=1. ; y=2. ; z=3. }
* ) ;;
* - : Coordinate.t = 2.0000 4.0000 6.0000
*
* Coordinate.(
* { x=1. ; y=2. ; z=3. } |+ { x=2. ; y=3. ; z=1. }
* );;
* - : Coordinate.t = 3.0000 5.0000 4.0000
*
* Coordinate.(
* { x=1. ; y=2. ; z=3. } |- { x=2. ; y=3. ; z=1. }
* );;
* - : Coordinate.t = -1.0000 -1.0000 2.0000
* #+end_example *)
(* [[file:~/QCaml/common/coordinate.org::*Vector operations][Vector operations:2]] *)
let get axis { x ; y ; z } =
match axis with
| X -> x
| Y -> y
| Z -> z
let ( |. ) s { x ; y ; z } =
make { x = s *. x ;
y = s *. y ;
z = s *. z ; }
let ( |+ )
{ x = x1 ; y = y1 ; z = z1 }
{ x = x2 ; y = y2 ; z = z2 } =
make { x = x1 +. x2 ;
y = y1 +. y2 ;
z = z1 +. z2 ; }
let ( |- )
{ x = x1 ; y = y1 ; z = z1 }
{ x = x2 ; y = y2 ; z = z2 } =
make { x = x1 -. x2 ;
y = y1 -. y2 ;
z = z1 -. z2 ; }
let neg a = -1. |. a
let dot
{ x = x1 ; y = y1 ; z = z1 }
{ x = x2 ; y = y2 ; z = z2 } =
x1 *. x2 +.
y1 *. y2 +.
z1 *. z2
let norm u =
sqrt ( dot u u )
(* Vector operations:2 ends here *)
(* Coordinates can be printed in bohr or angstrom. *)
(* [[file:~/QCaml/common/coordinate.org::*Printers][Printers:2]] *)
open Format
let pp ppf c =
fprintf ppf "@[@[%8.4f@] @[%8.4f@] @[%8.4f@]@]" c.x c.y c.z
let pp_bohr ppf c =
fprintf ppf "@[(@[%10f@], @[%10f@], @[%10f@] Bohr)@]" c.x c.y c.z
let pp_angstrom ppf c =
let c = bohr_to_angstrom c in
fprintf ppf "@[(@[%10f@], @[%10f@], @[%10f@] Angs)@]" c.x c.y c.z
(* Printers:2 ends here *)