anchor.diff:  ;;;
   ;;; Machine Learning Building Blocks
   
  +(defun average (array)
  +  (α #'/
  +     (β* #'+ 0 array)
  +     (total-size array)))
  +
   (defun make-random-array (dimensions &key (element-type 't))
     (let ((array (make-array dimensions :element-type element-type)))
       (loop for index below (array-total-size array) do
  
positive.code:          (upper-bounds (make-array k :initial-element 0))
           (filters
             (make-trainable-parameter
              (make-random-array n-filters :element-type (element-type array))))
           (d nil))
      ;; Determine the dimension of the stencil.
      (loop for offsets in stencil do
  
negative.code:   (α #'max (coerce 0 (element-type array)) array))
  
  (defun make-fully-connected-layer (array output-shape)
    (let* ((m (shape-size output-shape))
           (n (total-size array))
           (weights
             (make-trainable-parameter
              (α #'/
                 (make-random-array (list m n) :element-type (element-type array))
                 n)))
           (biases
             (make-trainable-parameter
              (α #'/
                 (make-random-array m :element-type (element-type array))
                 m))))
      (reshape
       (α #'+
          (β #'+
  