anchor.diff:  
        ;; Update weights-2.
        ;; We do this after weights-1 to maintain integrity.  Weights-1 is changed on the old weights-2 values, and weights-2 does not depend upon weights-1.
  -       (loop for i below (length hidden-node)
  +       (loop for i below numberofhiddennodes
   	    do
   	    (incf (aref weights-2 i)
   		  (* rate-of-learning
  
positive.code:        do
         (setf output-node-error-gradient (error-gradient-of-output-node dataset exemplar))
       ;; Calc hiddennode error gradients.  For use with updating weights-1
         (loop for i below (length hidden-node)	;For all hidden nodes.
  	    do
  	    (setf (aref hneg i)
  		  (* (aref weights-2 i)	;Weight of the hidden node
  
negative.code: 		     output-node-error-gradient)))
  
       ;; Update weights-1
         (loop for input-node-iterator below numberofinputnodes do
  	    (loop for hidden-node-iterator below numberofhiddennodes do
  		 (incf (aref weights-1 input-node-iterator hidden-node-iterator)
  		       (* rate-of-learning
  			  (funcall (aref input-node input-node-iterator) dataset exemplar)
  