changeset 47:e3d86a0f25b3

n-gram features

darcs-hash:20070615112417-f76cc-6cc8c9b58db4f04bf1793af6521cbb037dce485f.gz

--- a/utils/package.lisp	Fri Jun 15 12:12:02 2007 +0100
+++ b/utils/package.lisp	Fri Jun 15 12:24:17 2007 +0100
@@ -26,5 +26,8 @@
 	   #:levenshtein-distance
 	   #:beats-to-seconds
 	   #:get-n-grams
+	   #:inter-onset-intervals
+	   #:get-n-gram
+	   #:n-gram-stats
 	   #:monodificate
 	   ))

--- a/utils/utils.lisp	Fri Jun 15 12:12:02 2007 +0100
+++ b/utils/utils.lisp	Fri Jun 15 12:24:17 2007 +0100
@@ -359,4 +359,47 @@
 	       (>= (/ overs total)
 		   1/4))
 	  'T
-	  'nil))))
\ No newline at end of file
+	  'nil))))
+
+(defgeneric inter-onset-intervals (composition &key rounding-divisor))
+(defmethod inter-onset-intervals ((composition composition) &key (rounding-divisor 1/4))
+  ;; returns values - list inter-onset intervals in beats, modal i-o-i
+  ;; and i-o-is in seconds.
+  ;; ** Only makes sense for monodic music
+  ;; FIXME: Should this keep in objects or am I right to make numbers
+  ;; here?
+  ;; FIXME: Should I (do I) filter out 0s?
+  (let ((i-o-i-list) (i-o-i-secs-list) (prev)
+	(hits (make-array (/ 32 rounding-divisor))))
+    (loop for event being the elements of composition
+       do (progn
+	    (when prev
+	      (let* ((i-o-i-period (inter-onset-interval prev event))
+		     (i-o-i (duration i-o-i-period))
+		     (i-o-i-secs (amuse-utils:beats-to-seconds i-o-i-period composition)))
+		(when (= i-o-i-secs 0)
+		  (format t "~D, ~D -- " (timepoint prev) (timepoint event)))
+		(push i-o-i i-o-i-list)
+		(push i-o-i-secs i-o-i-secs-list)
+		(when (< i-o-i 32)
+		  ;; Not really interested in very long results for the
+		  ;; modal value anyway.
+		  (incf (aref hits (round i-o-i rounding-divisor))))))
+	    (setf prev event)))
+    (let ((mode '(0 0)))
+      ;; we want the position of the highest mode
+      (loop for i downfrom (1- (length hits)) to 0
+	 when (> (aref hits i) (car mode))
+	 do (setf mode (list (aref hits i) i)))
+      (values (reverse i-o-i-list)
+	      (* (cadr mode) rounding-divisor)
+	      (reverse i-o-i-secs-list)))))
+
+(defun pitch-interval-list (composition)
+  (let ((intervals)
+	(previous-event))
+    (sequence:dosequence (event composition (reverse intervals))
+      (when previous-event
+	(push (span (pitch- event previous-event))
+	      intervals))
+      (setf previous-event event))))
\ No newline at end of file