anchor.diff:  
   (defclass softmax-label-chunk* (softmax-label-chunk) ())
   
  +;;; Samplers don't return examples, but a list of (SAMPLE
  +;;; OMIT-LABEL-P). Work around it.
   (defmethod maybe-make-misclassification-measurer ((chunk softmax-label-chunk*))
     (let ((measurer (call-next-method)))
       (when measurer
  
positive.code:     (with-stripes ((stripe chunk start end))
        (- (max-position (storage (nodes chunk)) start end)
           start))))
  
  (defun make-dbn-reconstruction-misclassification-counters-and-measurers
      (dbn &key (rbm (last1 (rbms dbn))))
  
negative.code:   (unless (boundp '*test-images*)
      (setq *test-images* (load-test)))
    (flet ((train-dbn ()
             (init-mnist-dbn *dbn/2* :stddev '(0.001 0.01))
             (train-mnist-dbn *dbn/2* :n-epochs 100 :n-gibbs '(1 5)
                              :learning-rate '(0.05 0.01)
                              :decay 0.001 :visible-sampling t)
             (save-weights (merge-pathnames "mnist-2.dbn" *mnist-dir*)
  