#|

    class11.lsp   
 
    - Moving averages (simple smoother to write)
    
    - Animation with slider
    
    - Basic foreign functions

|#


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;;                                                         ;;
;;    Moving average simulation                            ;;
;;                                                         ;;
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;--- Function to generate test data  (saves truth as side effect)

(defun SINE-GEN (n sigma)
  (+ (setf TRUTH (sin (rseq 0 (* 2 pi) n)))
     (* sigma (normal-rand n))
     ))


;--- Pick parameters

(def n 1000)
(def noiseSD .5)


;--- Plot data and true function to estimate

(def xax (iseq n))
(def p (plot-points xax (setf DATA (sine-gen n noiseSD)) ))
(send p :add-lines xax truth :color 'magenta)


;--- Moving average estimator

(defun MOVING-AVERAGE (x width)
  "Smooths assuming input x is equally spaced."
  (unless (oddp width)
          (format t "Width needs to be odd integer.~%")
          (setf width (let ((rw (round width))  )
                        (if (oddp rw) rw (1+ rw))))   )
  (let ((half (/ (1- width) 2))      ; invariants done once
        (n-1  (1- (length x)))
        (smth ())  )
    (flet ((avg (i) 
                (mean (select x
                              (iseq (max 0   (- i half))
                                    (min n-1 (+ i half)))))  ))
      (dotimes (i (length x))
               (push (avg i) smth))
      (nreverse smth)
      )))


;--- Add smoothed data to plot, varying width of smoother

(send p :add-lines xax (moving-average data 15))

(send p :add-lines (lowess xax data) :color 'green)

(send p :clear-points)



;--- Smooth the smooth, "twicing"

(send p :add-lines
      xax (moving-average (moving-average data 30) 20)
      :color 'blue)


(plot-lines xax (moving-average (moving-average data 30) 50)
            :color 'blue)



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;;                                                         ;;
;;     Slider animation                                    ;;
;;                                                         ;;
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;--- Fun with animation, slider

(def sin (sample (iseq n) 100))         ; dont crowd the figure
(def p2 (plot-points (select xax sin)
                     (select data sin)))  


(apropos 'slider)           ; see page 226 of text

(defun draw (x)
     (send p2 :add-lines xax (moving-average data x))
     (send p2 :clear-lines))
))

          
(interval-slider-dialog            
 '(10 50)       ; limits on interval
 :points 25      ; divisions of interval
 :action #'draw)
         

(dolist (i '(3 5 10 15 20 25 30 35))
	(draw i))
               
;--- Too slow to be effective...   Try the compiler

(compile 'moving-average)
                 

;--- Better, but still pretty slow.



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;;                                                         ;;
;;     Foreign functions                                   ;;
;;                                                         ;;
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;--- Build C function with all passed as pointers

look at mean.c


;--- Compile this C function

cc -c +O3 -Aa +Z  mean.c
ld -o mean.CR -b mean.o


;--- Load the definition of this function into Lisp

(set-working-directory "/users/bob/html/stat540")

(dyn-load "/users/bob/html/stat540/mean.CR")


;--- Template 

(call-cfun name arg1 arg2 ... )

;--- Call cfun

(CALL-CFUN "myMean" (float (iseq 10))  10 7.7)