anchor.diff:        (- (max-position (storage (nodes chunk)) start end)
            start))))
   
  -(defun make-reconstruction-misclassification-counters-and-measurers
  +(defun make-dbn-reconstruction-misclassification-counters-and-measurers
       (dbn &key (rbm (last1 (rbms dbn))))
     (loop for chunk in (apply #'append
                               (mapcar #'chunks
                                       (subseq (rbms dbn)
                                               0 (1+ (position rbm (rbms dbn))))))
  +        for measurer = (maybe-make-misclassification-measurer chunk)
  +        when measurer
  +        collect (cons (make-instance 'error-counter)
  +                      measurer)))
  +
  +(defun make-bm-reconstruction-misclassification-counters-and-measurers (bm)
  +  (loop for chunk in (chunks bm)
           for measurer = (maybe-make-misclassification-measurer chunk)
           when measurer
           collect (cons (make-instance 'error-counter)
  
positive.code:    ;; has the same weight.
     :multiplier (/ (length batch)
                    (n-stripes (persistent-chains trainer)))))
  |#
  
negative.code:                                        (dbn rbm) :rbm rbm))
             (n-inputs trainer))
    (let ((counters-and-measurers
           (make-dbn-reconstruction-misclassification-counters-and-measurers
            (dbn rbm) :rbm rbm)))
      (when counters-and-measurers
        (let ((errors (map 'list
  