(defun make-usable (data)
  "make-usable: runs quicksort & cuts off the unneccessary class column"
  (adjust-array (quicksort-array data (- (array-dimension data 1) 1))
                (list (array-dimension data 0)
                      (- (array-dimension data 1) 1))))
    
(defun set-distance-matrix(datarray)
  "set-distance-matrix: Creates and returns an array representing the distances between all objects"
  (let ((distancearray
         (make-array (list (array-dimension datarray 0)
                           (array-dimension datarray 0)) :initial-element 0))
        (sum 0))    
    (dotimes (i (array-dimension datarray 0) distancearray)
      (dotimes (j (array-dimension datarray 0))
        (setf sum 0)
        (dotimes (k (array-dimension datarray 1))
          (setf sum (+ sum (expt (- (aref datarray i k)
                                    (aref datarray j k)) 2))))
        (setf (aref distancearray i j) (sqrt sum))))))

(defun set-distance-matrix2 (data1 data2)
  "set-distance-matrix2: Creates and returns an array representing the distances between objects of two sets"
  (let ((distancearray
         (make-array (list (array-dimension data1 0)
                           (array-dimension data2 0)) :initial-element 0))
        (sum 0))
    (dotimes (i (array-dimension distancearray 0) distancearray)
      (dotimes (j (array-dimension distancearray 1))
        (setf sum 0)
        (dotimes (k (array-dimension data1 1))
          (setf sum (+ sum (expt (- (aref data1 i k) (aref data2 j k)) 2))))
        (setf (aref distancearray i j) (sqrt sum))))))

(defun reduce-dist(oldist xmatrix column)
  "reduce-dist:reduces the distancematrix using another magic equation"
  (let ((reducedist (make-array (list (array-dimension oldist 0) (array-dimension oldist 1)) :initial-element 0)))
    
    (dotimes (i (array-dimension oldist 0) reducedist)
      (dotimes (j (array-dimension oldist 1))
        (setf (aref reducedist i j)
              (sqrt (- (expt (aref oldist i j) 2)
                       (expt (- (aref xmatrix i column)
                                (aref xmatrix j column)) 2))))
        (if (complexp (aref reducedist i j))
            (setf (aref reducedist i j) 0))))))

(defun dist(distmatrix  a)
  "returns the number of the object furthest from a,
   according to the distmatrix"
  (let ((b 0)
        (temp 0))    
    (dotimes (i (array-dimension distmatrix 0) b)
      (cond ((> (aref distmatrix a i) temp)
             (setf temp (aref distmatrix a i))
             (setf b i))))))