0xm00n

use std::f64;

// sigmoid activation function
fn sigmoid(x: f64) -> f64 {
    1.0 / (1.0 + (-x).exp())
}

// derivative of the sigmoid function
fn sigmoid_prime(x: f64) -> f64 {
    sigmoid(x) * (1.0 - sigmoid(x))

0xm00n

type complex = {re: float; im: float}

let complex_add a b = {re = a.re +. b.re; im = a.im +. b.im}
let complex_sub a b = {re = a.re -. b.re; im = a.im -. b.im}
let complex_mul a b = {re = a.re *. b.re -. a.im *. b.im; im = a.re *. b.im +. a.im *. b.re}
let complex_exp theta = {re = cos theta; im = sin theta}

let rec fft x =
  let n = Array.length x in
  if n <= 1 then x

0xm00n

type complex = {re: float; im: float}

let complex_add a b = {re = a.re +. b.re; im = a.im +. b.im}
let complex_mul a b = {re = a.re *. b.re -. a.im *. b.im; im = a.re *. b.im +. a.im *. b.re}
let complex_exp theta = {re = cos theta; im = sin theta}

let idft x =
  let n_total = Array.length x in
  let x_n n =
    let sum = ref {re = 0.0; im = 0.0} in

0xm00n

(* complex num ops*)
type complex = {re: float; im: float}

let complex_add a b = {re = a.re +. b.re; im = a.im +. b.im} 
let complex_sub a b = {re = a.re -. b.re; im = a.im -. b.im}
let complex_mul a b = {re = a.re *. b.re -. a.im *. b.im; im = a.re *. b.im +. a.im *. b.re}
(* exponential of a complex number given angle in radians*)
let complex_exp theta = {re = cos theta; im = sin theta}

(* discrete fourier transform*)