Function: ROUND-HALF-DOWN

Documentation

Round towards the nearest legal value. If the current value is exactly half way between two legal values round towards 0.

Source

(defun round-half-down (number &optional (precision *precision*))
  "Round towards the nearest legal value. If the current value is
exactly half way between two legal values round towards 0."
  (multiple-value-bind (value discarded)
      (floor number)
    (if (< 1/2 discarded)
	(/ (1+ value) precision)
        (/ value precision))))