In Progress finding the value for sigmoid'(x) = 1

sigmoid-prime.clj

; This doesn't work yet ;)

(defn sigmoid [x] (/ 1 (- 1 (Math/exp (- x)))))
(defn sigmoid' [x] (let [sigmoidx (sigmoid x)] (* sigmoidx (- 1 sigmoidx))))


(defn bs [f ^double val ^double delta]
  (loop [bottom -100.0 top 100.0 countdown 1000]
    (let [middle ^double (+ bottom (/ (- top bottom) 2))
          f-mid ^double (f middle)]
      (if (= 0 countdown)
        (prn "aborting - f-mid was " f-mid)
        (do
          (prn bottom middle f-mid top)
          (cond (<= (Math/abs (- f-mid val)) delta) middle
                (< val f-mid) (recur bottom middle (dec countdown))
                :else (recur middle top (dec countdown))))))))

(bs sigmoid 1.0 0.1)