anchor.diff:     (weight :accessor weight :initarg :weight :initform 1.0 :type real)
      (delta :accessor delta :initform 0.0 :type real))
     (:documentation "Describes a neural connection to TARGET neuron.  WEIGHT represents the strength of the connection and DELTA contains the last change in WEIGHT.  TARGET is required."))
  -
  -
   
   (defclass t-neuron ()
     ((net :reader net :initarg :net :initform (error ":net required") :type t-net)
  
positive.code:             (report-function function)
              (time-span-between-reports integer))
      (loop
         initially (with-open-file (stream "/tmp/training.log" :direction :output :if-exists :append)
                     (format stream "time-span-between-reports: ~a~%" time-span-between-reports))
         ;; with vec = (tset-list-to-tset-vectors t-set)
         ;; with shuffled-vector-indices =
         ;;   (shuffle (loop for a from 0 below (length vec) collect a))
  
negative.code:                     ((= layer-index (1- (length (topology net)))) :output)
                      (t :hidden))
                :neuron-count (elt (topology net) layer-index)
                :transfer-tag
                (if (or (zerop layer-index)
                        (= layer-index (1- (length (topology net)))))
                    :logistic
                    (transfer-tag net))
                :net net)))
    (loop for layer in (layers net)
       for next-layer = (if (eql (layer-type layer) :output)
  