(defun unif (a b)
  (+ a (* (- b a) (first (uniform-rand 1))))
  )

(defun norm (n alpha)
  (let ((vec (iseq n))
	(x 0)
	)
    (setf (select vec 0) x)
    (dolist (i (iseq 1 (- n 1)))
      (let* ((innov (unif (- 0 alpha) alpha))
	     (can (+ x innov))
	     (aprob (min 1 (/ (normal-dens can) (normal-dens x))))
	     (u (unif 0 1))
	     )
	(if (< u aprob)
	    (setf x can)
	  )
	(setf (select vec i) x)
	)
      )
    vec
    )
  )



(def nvec (norm 10000 100))
(histogram nvec)
(plot-lines (iseq (length nvec)) nvec)















;; end