+ updated to version 0.1.03

+ testing
+ removed bug in find() + cascades
+ example test sketches added for PMF(), VAL(), CDF().

libraries/Histogram/examples/hist_test/hist_test.ino

@@ -0,0 +1,91 @@
+//
+//    FILE: hist_test.pde
+//  AUTHOR: Rob Tillaart
+//    DATE: 2012-12-23
+//
+// PUPROSE: test histogram frequency
+//
+
+#include "histogram.h"
+
+// double b[] = { 0, 100, 200, 300, 325, 350, 375, 400, 500, 600, 700, 800, 900, 1000 };
+
+double b[] = { 
+  0, 100, 200, 300, 325, 350, 375 };
+
+Histogram hist(7, b);
+
+unsigned long lastTime = 0;
+const unsigned long threshold = 50;  // milliseconds, for updating display
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.print("\nHistogram version: ");
+  Serial.println(HISTOGRAM_LIB_VERSION);
+
+  Serial.print("# buckets: ");
+  Serial.println(hist.size());
+
+  for (int i = 0; i < hist.size()-1; i++)
+  {
+    Serial.print("\t");  
+    Serial.print(b[i], 2);  
+  }
+  Serial.println();
+
+  for (int i = 0; i < hist.size()-1; i++)
+  {
+    Serial.print("\t");  
+    Serial.print(hist.find(b[i]));  
+  }
+  Serial.println();
+}
+
+void loop()
+{
+  // choose a "generator" for histogram data
+  // int x = analogRead(A0);
+  
+  int x = random(600) - 50;  // below lower limit
+  
+  //  int x = random(25);  
+  //  x = x*x;
+
+
+  //  Serial.print(x);
+  //  Serial.print("\t");
+  //  Serial.println(hist.find(x));
+  hist.add(x);
+
+  // update output 
+  unsigned long now = millis();
+  if (now - lastTime > threshold)
+  {
+    lastTime = now;
+    Serial.print(hist.count());
+    for (int i = 0; i < hist.size(); i++)
+    {
+      Serial.print("\t");
+      // gives percentage per bucket
+      // Serial.print(hist.bucket(i));   
+      Serial.print(hist.frequency(i), 2);  
+    }
+    // quartiles
+    // to get at least 25% of the values you must count all values < hist.VAL(0.25);
+    Serial.print("\t");
+    Serial.print(hist.VAL(0.25), 2);
+    // to get at least 50% of the values you must count all values < hist.VAL(0.50);
+    Serial.print("\t");
+    Serial.print(hist.VAL(0.50), 2);
+    Serial.print("\t");
+    Serial.print(hist.VAL(0.75), 2);
+    Serial.print("\t");
+    Serial.print(hist.VAL(1.0), 2);
+    Serial.println();
+
+    if (hist.count() > 10000UL) hist.clear();
+  }
+}
+
+

libraries/Histogram/examples/hist_test_cdf/hist_test_cdf.ino

@@ -0,0 +1,42 @@
+//
+//    FILE: hist_test_cdf.ino
+//  AUTHOR: Rob Tillaart
+//    DATE: 2012-11-10
+//
+// PUPROSE: test histogram library
+//
+
+#include "histogram.h"
+
+double b[] = { 
+  0, 300, 325, 350, 375, 400, 1000 };
+
+Histogram hist(7, b);
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println("\ntest CDF");
+  Serial.print("Histogram version: ");
+  Serial.println(HISTOGRAM_LIB_VERSION);
+}
+
+void loop()
+{
+  int x = random(1000);
+  hist.add(x);
+
+  Serial.print(hist.count());
+  Serial.print("\t");
+  for (int i = 0; i < (hist.size() -1); i++)
+  {
+    Serial.print(hist.CDF(b[i]), 2);
+    Serial.print("\t");
+  }
+  Serial.println();
+
+  if (hist.count() > 1000) hist.clear();
+
+  delay(10);
+}
+

libraries/Histogram/examples/hist_test_pmf/hist_test_pmf.ino

@@ -0,0 +1,44 @@
+//
+//    FILE: hist_test_pmf.ino
+//  AUTHOR: Rob Tillaart
+//    DATE: 2012-11-10
+//
+// PUPROSE: test histogram library
+//
+
+#include "histogram.h"
+
+double b[] = { 
+  0, 50, 100, 150, 200, 250, 
+  300, 350, 400, 450, 500, 
+  600, 700, 800, 900, 1000 };
+
+Histogram hist(16, b);
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println("\ntest PMF");
+  Serial.print("Histogram version: ");
+  Serial.println(HISTOGRAM_LIB_VERSION);
+}
+
+void loop()
+{
+  int x = random(1000);
+  hist.add(x);
+
+  Serial.print(hist.count());
+  Serial.print("\t");
+  for (int i = 0; i < hist.size()-1; i++)
+  {
+    Serial.print(hist.PMF(b[i]), 2);
+    Serial.print("\t");
+  }
+  Serial.println();
+
+  if (hist.count() > 1000) hist.clear();
+
+  delay(10);
+}
+

libraries/Histogram/examples/hist_test_val/hist_test_val.ino

@@ -0,0 +1,56 @@
+//
+//    FILE: hist_test_val.ino
+//  AUTHOR: Rob Tillaart
+//    DATE: 2012-11-11
+//
+// PUPROSE: test histogram library
+//
+
+#include "histogram.h"
+
+double b[] = { 
+  0, 50, 100, 150, 200, 250, 
+  300, 350, 400, 450, 500, 
+  600, 700, 800, 900, 1000 };
+
+Histogram hist(16, b);
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println("\ntest VAL");
+  Serial.print("Histogram version: ");
+  Serial.println(HISTOGRAM_LIB_VERSION);
+}
+
+void loop()
+{
+  int x = random(800);
+  hist.add(x);
+
+  Serial.print(hist.count());
+  Serial.print(", ");
+  float f = 0.5;
+  Serial.print(f, 2);
+  Serial.print(" : ");
+  
+  Serial.print(hist.VAL(f), 2);
+  Serial.print("\t");
+  
+  float sum = 0;
+  int i = 0;
+  for (i = 0; i< hist.size(); i++)
+  {
+    sum += hist.frequency(i);
+    Serial.print(sum, 2);
+    Serial.print("\t");
+    if (sum >= f) break;
+  }
+  Serial.print(b[i]);
+  Serial.println();
+
+  if (hist.count() > 1000) hist.clear();
+
+  delay(10);
+}
+

libraries/Histogram/histogram.cpp

@@ -1,24 +1,29 @@
 //
-//    FILE: histogram.cpp
-//  AUTHOR: Rob dot Tillaart at gmail dot com  
-// VERSION: see HISTOGRAM_LIB_VERSION in .h
+//
+//    FILE: Histogram.h
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.03
 // PURPOSE: Histogram library for Arduino
+//    DATE: 2012-11-10
+//
+// Released to the public domain
 //
 // HISTORY:
 // 0.1.0 - 2012-11-10 initial version
 // 0.1.1 - 2012-11-10 added PMF() and CDF()
 // 0.1.2 - 2012-12-23 changed float to double; some comments
+// 0.1.03 - 2013-09-29 testing a lot & refactoring
 //
 // Released to the public domain
 //
 
 #include "histogram.h"
 
-Histogram::Histogram(uint8_t len, double *bounds)
+Histogram::Histogram(int len, double *bounds)
 {
     _bounds = bounds;
-	_len = len;
-	_data = (long*) malloc((len+1) * sizeof(long)); 
+    _len = len+1;
+    _data = (long*) malloc((_len) * sizeof(long));
     clear();
 }
 
@@ -30,7 +35,7 @@ Histogram::~Histogram()
 // resets all counters
 void Histogram::clear()
 {
-	for (uint8_t i = 0; i < _len+1; i++)
+    for (uint8_t i = 0; i < _len; i++)
     {
         _data[i] = 0;
     }
@@ -54,7 +59,7 @@ void Histogram::sub(double f)
 // returns the number of buckets
 uint8_t Histogram::size()
 {
-	return _len+1;
+    return _len;
 }
 
 // returns the number of values added
@@ -66,7 +71,7 @@ unsigned long Histogram::count()
 // returns the count of a bucket
 long Histogram::bucket(uint8_t idx)
 {
-	if (idx > _len+1) return 0;
+    if (idx > _len) return 0;
     return _data[idx];
 }
 
@@ -74,10 +79,11 @@ long Histogram::bucket(uint8_t idx)
 double Histogram::frequency(uint8_t idx)
 {
     if (_cnt == 0) return NAN;
-	if (idx > _len+1) return 0;
+    if (idx > _len) return 0;   // diff with PMF
     return (1.0 * _data[idx]) / _cnt;
 }
 
+// EXPERIMENTAL
 // returns the probability of the bucket of a value
 double Histogram::PMF(double val)
 {
@@ -86,6 +92,7 @@ double Histogram::PMF(double val)
     return (1.0 *_data[idx]) / _cnt;
 }
 
+// EXPERIMENTAL
 // returns the cummulative probability of
 // values <= value
 double Histogram::CDF(double val)
@@ -93,7 +100,10 @@ double Histogram::CDF(double val)
     if (_cnt == 0) return NAN;
     uint8_t idx = find(val);
     long sum = 0;
-	for (uint8_t i=0; i<= idx; i++) sum += _data[i];
+    for (uint8_t i=0; i<= idx; i++)
+    {
+        sum += _data[i];
+    }
     return (1.0 * sum) / _cnt;
 }
 
@@ -106,21 +116,27 @@ double Histogram::VAL(double prob)
     if (prob < 0.0) prob = 0.0;
     if (prob > 1.0) prob = 1.0;
 
+    double value = prob * _cnt;
     long sum = 0;
-	for (uint8_t i = 0; i <= _len; i++)
+    for (uint8_t i = 0; i < _len; i++)
     {
         sum += _data[i];
-		if (sum >= (prob * _cnt)) return _bounds[i];
+        if (sum >= value && (i <(_len-1)) ) return _bounds[i];
     }
     return INFINITY;
 }
 
-// returns the bucket number for value f
-uint8_t Histogram::find(double f)
+// returns the bucket number for value val
+uint8_t Histogram::find(double val)
 {
-	uint8_t i = 0;
-	while(i < _len && f > _bounds[i]) i++;
-	return i;
+    for (uint8_t i = 0; i< (_len-1); i++)
+    {
+        if (_bounds[i] >= val) return i;
+    }
+    return _len-1;
+    // uint8_t i = 0;
+    // while ((i < (_len-1)) && (_bounds[i] < val)) i++;
+    // return i;
 }
 
 // END OF FILE

libraries/Histogram/histogram.h

@@ -2,9 +2,10 @@
 #define Histogram_h
 //
 //    FILE: Histogram.h
-//  AUTHOR: Rob dot Tillaart at gmail dot com  
+//  AUTHOR: Rob Tillaart
+// VERSION: 0.1.03
 // PURPOSE: Histogram library for Arduino
-// HISTORY: See Histogram.cpp
+//    DATE: 2012-11-10
 //
 // Released to the public domain
 //
@@ -13,19 +14,28 @@
 #include <math.h>
 #include <inttypes.h>
 
-#define HISTOGRAM_LIB_VERSION "0.1.1"
+#if defined(ARDUINO) && ARDUINO >= 100
+#include "Arduino.h"
+#else
+#include "WProgram.h"
+#endif
+
+#define HISTOGRAM_LIB_VERSION "0.1.03"
 
 class Histogram
 {
-	public:
-	Histogram(uint8_t len, double *bounds);
+public:
+    Histogram(int len, double *bounds);
     ~Histogram();
+
     void clear();
     void add(double val);
     void sub(double val);
+
     uint8_t size();
     unsigned long count();
     long bucket(uint8_t idx);
+
     double frequency(uint8_t idx);
     double PMF(double val);
     double CDF(double val);