1 files changed, 64 insertions(+), 9 deletions(-)

M rgr-pumpernickel.el

@@ 27,6 27,66 @@
 	  (days-to-time (- days (time-to-days 0)))))
     (format-time-string "%Y-%m-%d" time)))
 
+(defun rgr-pump--draw-histogram (hist)
+  ;; hist is an alist of (days . count) sorted in descending order of count.  We
+  ;; rely on the fact that days are all divisible by 7, the days are mostly on
+  ;; the order of 3-16 weeks, and we're interested in probabilities rather than
+  ;; raw counts so we can hardwire the geometry.  Note that we skip (0,0).
+  (let ((total 0)
+	(max-count 0) (max-days 0)
+	(chars-per-count 0)
+	(histogram nil))
+    ;; Find total, max-count, and max-days.
+    (dolist (pair hist)
+      (let ((days (car pair)) (count (cdr pair)))
+	(cl-incf total count)
+	(when (< max-count count)
+	  (setq max-count count))
+	(when (< max-days days)
+	  (setq max-days days))))
+    ;; Make the histogram ten characters high.
+    (setq chars-per-count (/ 10.0 max-count))
+    ;; Build a histogram of weeks as a vector.
+    (unless (zerop (mod max-days 7))
+      (error "the fundamental assumption of weeks is broken"))
+    (setq histogram (make-vector (1+ (floor max-days 7)) 0))
+    (dolist (pair hist)
+      (let ((days (car pair)) (count (cdr pair)))
+	(setf (aref histogram (floor days 7)) count)))
+    ;; Allocate three characters to each week.
+    (cl-do ((height 9 (1- height))
+	    (str (make-string (* (length histogram) 3) ?\ )
+		 (make-string (* (length histogram) 3) ?\ )))
+	   ((<= height 0))
+      (dotimes (idx (length histogram))
+	(when (and (> idx 0)
+		   (>= (* (aref histogram idx) chars-per-count) height))
+	  (setf (aref str (+ 2 (* idx 3))) ?\*)))
+      (insert (replace-regexp-in-string " +$" "" str) "\n"))
+    (insert "   ")	;; the missing zero.
+    (dotimes (idx (length histogram))
+      (when (> idx 0)
+	(insert (format "%3d" idx))))
+    (insert "  weeks\n")))
+
+(defun rgr-pump--make-prediction (last-day n hist)
+  ;; last-day is the rgr-date-to-day of the most recent pumpernickel week for
+  ;; basing predictions, hist is an alist of (days . count) sorted in descending
+  ;; order of count, and n is the total count.  Show all predicted dates with
+  ;; more than 20% of the total probability.
+  (insert "\nNext week is estimated to start ")
+  (let ((need-comma nil))
+    (dolist (pair hist)
+      (let ((prob (/ (* (cdr pair) 100.0) n)))
+	(when (>= prob 20)
+	  (insert (if need-comma ", or " "")
+		  (format "%s (%d%%)"
+			  (rgr-format-days (+ last-day (car pair)))
+			  prob))
+	  (setq need-comma t)))))
+  (insert ".\n")
+  (fill-paragraph))
+
 ;;;###autoload
 (defun rgr-show-pumpernickel-intervals ()
   "Print a table of intervals between known pumpernickel weeks.


@@ 66,15 126,10 @@ The dominant intervals correspond (so far) to 6 or 5 weeks."
 	      (cl-incf n count)
 	      (push (cons i count) hist))))
 	(setq hist (sort hist #'(lambda (a b) (> (cdr a) (cdr b)))))
-	(insert
-	 (apply #'format
-		"\nNext week is estimated to start %s or %s.\n"
-		(mapcar #'(lambda (pair)
-			    (when pair
-			      (format "%s (%d%%)"
-				      (rgr-format-days (+ last-day (car pair)))
-				      (/ (* (cdr pair) 100.0) n))))
-			(list (car hist) (car (cdr hist))))))))))
+	;; (insert (prin1-to-string hist))
+	(insert "\n")
+	(rgr-pump--draw-histogram hist)
+	(rgr-pump--make-prediction last-day n hist)))))
 
 ;; (/ (rgr-days-between "2023 Dec 13" "2023 Oct 18") 7) 8