felipetavares

#lang racket

;; Week 1

;; There are two protocols in secure communication:
;; - handshake protocol: finding a shared key
;; - record layer: sending and receiving data
;;
;; Encrypting files is the same as sending encrypted
;; messages between A -> B, except B is actually A in

felipetavares

#lang racket

(require math/matrix)

(define (sigmoid x) (/ (exp x) (+ (exp x) 1)))
(define (sigmoid~ x) (* (sigmoid x) (- 1 (sigmoid x))))
(define (tanh~ x) (/ 1 (expt (cosh x) 2)))

(define activation sigmoid)
(define activation~ sigmoid~)

felipetavares

"""
Backwards difference

∇fᵢ = (fᵢ - fᵢ₋₁)
"""
function ∇(power, f, i)
    if power > 1
        ∇(power-1, f, i) - ∇(power-1, f, i-1)
    else
        f[i] - f[i-1]