From 328d4920c9c2330275510df912e03990f79e1f41 Mon Sep 17 00:00:00 2001
From: sshlien <fy733@ncf.ca>
Date: Thu, 21 Mar 2024 13:49:52 -0400
Subject: [PATCH] 2024.03.21

---
 VERSION        |  2 +-
 doc/readme.txt |  2 +-
 midistats.c    | 28 +++++++++++++++++++++++++++-
 3 files changed, 29 insertions(+), 3 deletions(-)

diff --git a/VERSION b/VERSION
index 5b1363d..4ccabc4 100644
--- a/VERSION
+++ b/VERSION
@@ -1,2 +1,2 @@
-March 18 2024
+March 21 2024
 
diff --git a/doc/readme.txt b/doc/readme.txt
index bb2b7c7..cd6dc02 100644
--- a/doc/readme.txt
+++ b/doc/readme.txt
@@ -6,7 +6,7 @@ abc2abc  version 2.21 February 19 2024
 yaps     version 1.93 February 19 2024
 abcmatch version 1.83 February 19 2024
 midicopy version 1.39 November 08 2022
-midistats version 0.90 March 18 2024
+midistats version 0.91 March 21 2024
 
 24th January 2002
 Copyright James Allwright
diff --git a/midistats.c b/midistats.c
index dddce7c..18215b5 100644
--- a/midistats.c
+++ b/midistats.c
@@ -17,7 +17,7 @@
  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA
 */
  
-#define VERSION "0.90 March 18 2024 midistats"
+#define VERSION "0.91 March 21 2024 midistats"
 
 /* midistrats.c is a descendent of midi2abc.c which was becoming to
    large. The object of the program is to extract statistical characterisitic 
@@ -65,6 +65,7 @@ extern char* strchr();
 void initfuncs();
 void stats_finish();
 float histogram_perplexity (int *histogram, int size); 
+float histogram_entropy (int *histogram, int size); 
 void stats_noteoff(int chan,int pitch,int vol);
 void stats_eot ();
 void keymatch();
@@ -637,6 +638,7 @@ printf("\ntrkact ");
   lasttrack++;
   for (i=0;i<lasttrack;i++) printf("% 5d",trkactivity[i]);
 printf("\npitchperplexity %f\n",histogram_perplexity(pitchclass_activity,12));
+printf("\npitchentropy %f\n",histogram_entropy(pitchclass_activity,12));
 printf("totalrhythmpatterns =%d\n",nrpatterns);
 printf("collisions = %d\n",ncollisions);
 if (hasLyrics) printf("Lyrics\n");
@@ -670,6 +672,30 @@ float histogram_perplexity (int *histogram, int size)
   return pow(2.0,-entropy/log(2.0));
   } 
 
+float histogram_entropy (int *histogram, int size) 
+  {
+  /* The perplexity is 2 to the power of the entropy */
+  int i;
+  int total;
+  float entropy;
+  float e,p;
+  total = 0;
+  entropy = 0.0;
+  //printf("\nhistogram_entropy of:");
+  for (i=0;i<size;i++) {
+    total += histogram[i];
+    //printf(" %d",histogram[i]);
+    } 
+  for (i=0;i<size;i++) {
+    if (histogram[i] < 1) continue;
+    p = (float) histogram[i]/total;
+    e = p*log(p);
+    entropy = entropy + e;
+    } 
+  //printf("\n");
+  return -entropy/log(2.0);
+  } 
+