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(*                                                                        *)
(*                                 OCaml                                  *)
(*                                                                        *)
(*             Xavier Leroy, projet Cristal, INRIA Rocquencourt           *)
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(*   Copyright 2002 Institut National de Recherche en Informatique et     *)
(*     en Automatique.                                                    *)
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(*   All rights reserved.  This file is distributed under the terms of    *)
(*   the GNU Lesser General Public License version 2.1, with the          *)
(*   special exception on linking described in the file LICENSE.          *)
(*                                                                        *)
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(** Complex numbers.

    This module provides arithmetic operations on complex numbers.
    Complex numbers are represented by their real and imaginary parts
    (cartesian representation).  Each part is represented by a
    double-precision floating-point number (type [float]).   *)

type t = { re: float; im: float }
(** The type of complex numbers.  [re] is the real part and [im] the
    imaginary part. *)

val zero: t
(** The complex number [0]. *)

val one: t
(** The complex number [1]. *)

val i: t
(** The complex number [i]. *)

val neg: t -> t
(** Unary negation. *)

val conj: t -> t
(** Conjugate: given the complex [x + i.y], returns [x - i.y]. *)

val add: t -> t -> t
(** Addition *)

val sub: t -> t -> t
(** Subtraction *)

val mul: t -> t -> t
(** Multiplication *)

val inv: t -> t
(** Multiplicative inverse ([1/z]). *)

val div: t -> t -> t
(** Division *)

val sqrt: t -> t
(** Square root.  The result [x + i.y] is such that [x > 0] or
    [x = 0] and [y >= 0].
    This function has a discontinuity along the negative real axis. *)

val norm2: t -> float
(** Norm squared: given [x + i.y], returns [x^2 + y^2]. *)

val norm: t -> float
(** Norm: given [x + i.y], returns [sqrt(x^2 + y^2)]. *)

val arg: t -> float
(** Argument.  The argument of a complex number is the angle
    in the complex plane between the positive real axis and a line
    passing through zero and the number.  This angle ranges from
    [-pi] to [pi].  This function has a discontinuity along the
    negative real axis. *)

val polar: float -> float -> t
(** [polar norm arg] returns the complex having norm [norm]
    and argument [arg]. *)

val exp: t -> t
(** Exponentiation.  [exp z] returns [e] to the [z] power. *)

val log: t -> t
(** Natural logarithm (in base [e]). *)

val pow: t -> t -> t
(** Power function.  [pow z1 z2] returns [z1] to the [z2] power. *)