anchor.diff:          (rowNum (1- (elt (array-dimensions X) 0))))
       (setf result
             (loop for c from 0 to colNum collect
  +               (/
                   (loop for r from 0 to rowNum for temp = (array-slice X r) sum
                        (* (- (logistic-regression (array-multiply temp theta)) (elt y r))
  -                        (elt temp c)))))
  +                        (elt temp c)))
  +               (1+ rowNum))))
       result))
   
   (defun gradient-descent-lr (X theta y alpha iterTime)
  
positive.code:       (loop for ind from 0 to (1- (length theta)) do
             (setf (elt theta ind)
                   (- (elt theta ind) (* alpha (elt pd ind)))))
        (print theta))))
  
  ;;; exercise below
  
  
negative.code:       (loop for ar in (read-data "./testdata/ex2data1.txt") collect
             (elt ar 2)))
  
  (defvar *theta*)
  (setf *theta* (make-array 3 :initial-element 0))
  
  (compute-cost *X* *theta* *y*)
  (partial-derivative-lr *X* *theta* *y*)
  