; column is one of num sym. contains class hash. which contains prim

(defklass counts ()
  (every (gensym "ALL"))
  (all   (make-hash-table))
  )

(defklass syms (counts))
(defklass nums (counts))

(defmethod counter ((x syms)) (make-instance 'sym))
(defmethod counter ((x nums)) (make-instance 'num))

(defun adds (c where new)
  (adds1 c new where)
  (adds1 c new (counts-every c))
  c)

(defun adds1 (c  new where)
  (let ((old (gethash where (counts-all c))))
    (setf old (add (or old (counter c)) 
		   new))))

(defklass count1 () 
  (n 0))

(defklass sym (count1)
  (uniques (make-hash-table))
  (cardinality 0)
  (m 1)
)

(defklass num (count1)
  (min most-positive-long-float)
  (max least-negative-double-float)
  (sum 0)
  (sumSq 0)
  ready
  mean
  stdev)

(defmethod add ((this sym) new)
  (in sym this
      (let ((old (incf (gethash new uniques 0))))
	(incf n)
	(if (= 1 old) 
	    (incf cardinality))))
  this)

(defmethod add ((this num) new)
  (in num this
      (setf min   (min min new)
	    max   (max max new)
	    ready nil
	    sum   (+ sum new)
	    sumSq (+ sumSq (* new new))
	    n     (1+ n)))
  this)

(defmethod probs ((this counts) where x)
  (prob1 (gethash where (counts-all this)) x))
  
(defmethod prob1 ((this sym) x)
  (/ (+ (sym-m this) 
	(gethash x (sym-uniques this) 0))
     (count1-n this)))

(defmethod prob1 ((this num) x)
  (in num this
      (unless ready
	(setf ready t
	      mean  (/ sum n )
	      stdev (sqrt (/ (- sumSq 
				(/ (expt sum 2) n)) 
			     (- n 1)))))
      (* (/ (* (sqrt (* 2 pi)) stdev))
	 (exp (* (- (/ (* 2 (expt stdev 2)))) 
		 (expt  (- x mean) 2))))))