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https://github.com/RobTillaart/Arduino.git
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144 lines
2.9 KiB
C++
144 lines
2.9 KiB
C++
//
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//
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// FILE: Histogram.h
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// AUTHOR: Rob Tillaart
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// VERSION: 0.1.04
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// PURPOSE: Histogram library for Arduino
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// DATE: 2012-11-10
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//
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// Released to the public domain
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//
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// HISTORY:
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// 0.1.0 - 2012-11-10 initial version
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// 0.1.1 - 2012-11-10 added PMF() and CDF()
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// 0.1.2 - 2012-12-23 changed float to double; some comments
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// 0.1.03 - 2013-09-29 testing a lot & refactoring
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// 0.1.04 - 2015-03-06 stricter interface
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//
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// Released to the public domain
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//
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#include "histogram.h"
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Histogram::Histogram(const uint8_t len, double *bounds)
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{
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_bounds = bounds;
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_len = len + 1;
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_data = (long*) malloc((_len) * sizeof(long));
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clear();
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}
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Histogram::~Histogram()
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{
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free(_data); // free may still have a bug :(
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}
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// resets all counters
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void Histogram::clear()
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{
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for (uint8_t i = 0; i < _len; i++)
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{
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_data[i] = 0;
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}
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_cnt = 0;
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}
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// adds a new value to the histogram - increasing
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void Histogram::add(const double f)
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{
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_data[find(f)]++;
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_cnt++;
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}
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// adds a new value to the histogram - decreasing
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void Histogram::sub(const double f)
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{
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_data[find(f)]--;
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_cnt++;;
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}
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// returns the number of buckets
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uint8_t Histogram::size()
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{
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return _len;
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}
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// returns the number of values added
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unsigned long Histogram::count()
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{
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return _cnt;
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}
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// returns the count of a bucket
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long Histogram::bucket(const uint8_t idx)
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{
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if (idx > _len) return 0;
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return _data[idx];
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}
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// returns the relative frequency of a bucket
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double Histogram::frequency(const uint8_t idx)
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{
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if (_cnt == 0) return NAN;
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if (idx > _len) return 0; // diff with PMF
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return (1.0 * _data[idx]) / _cnt;
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}
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// EXPERIMENTAL
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// returns the probability of the bucket of a value
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double Histogram::PMF(const double val)
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{
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if (_cnt == 0) return NAN;
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uint8_t idx = find(val);
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return (1.0 *_data[idx]) / _cnt;
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}
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// EXPERIMENTAL
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// returns the cummulative probability of
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// values <= value
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double Histogram::CDF(const double val)
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{
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if (_cnt == 0) return NAN;
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uint8_t idx = find(val);
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long sum = 0;
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for (uint8_t i=0; i<= idx; i++)
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{
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sum += _data[i];
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}
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return (1.0 * sum) / _cnt;
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}
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// EXPERIMENTAL
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// returns the value of the original array for
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// which the CDF is at least prob.
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double Histogram::VAL(const double prob)
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{
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if (_cnt == 0) return NAN;
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double p = prob;
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if (p < 0.0) p = 0.0;
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if (p > 1.0) p = 1.0;
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double value = p * _cnt;
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long sum = 0;
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for (uint8_t i = 0; i < _len; i++)
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{
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sum += _data[i];
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if (sum >= value && (i <(_len-1)) ) return _bounds[i];
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}
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return INFINITY;
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}
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// returns the bucket number for value val
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uint8_t Histogram::find(const double val)
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{
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for (uint8_t i = 0; i< (_len-1); i++)
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{
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if (_bounds[i] >= val) return i;
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}
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return _len-1;
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// uint8_t i = 0;
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// while ((i < (_len-1)) && (_bounds[i] < val)) i++;
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// return i;
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}
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// END OF FILE
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