mirror of
https://github.com/RobTillaart/Arduino.git
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374 lines
7.4 KiB
C++
374 lines
7.4 KiB
C++
//
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// FILE: RunningMedian.cpp
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// AUTHOR: Rob Tillaart
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// VERSION: 0.3.9
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// PURPOSE: RunningMedian library for Arduino
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#include "RunningMedian.h"
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RunningMedian::RunningMedian(const uint8_t size)
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{
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_size = size;
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if (_size < MEDIAN_MIN_SIZE) _size = MEDIAN_MIN_SIZE;
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#if !RUNNING_MEDIAN_USE_MALLOC
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if (_size > MEDIAN_MAX_SIZE) _size = MEDIAN_MAX_SIZE;
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#endif
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#if RUNNING_MEDIAN_USE_MALLOC
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_values = (float *) malloc(_size * sizeof(float));
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_sortIdx = (uint8_t *) malloc(_size * sizeof(uint8_t));
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#endif
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clear();
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}
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RunningMedian::~RunningMedian()
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{
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#if RUNNING_MEDIAN_USE_MALLOC
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free(_values);
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free(_sortIdx);
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#endif
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}
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// resets all internal counters
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void RunningMedian::clear()
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{
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_count = 0;
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_index = 0;
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_sorted = false;
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for (uint8_t i = 0; i < _size; i++)
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{
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_sortIdx[i] = i;
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}
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}
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// adds a new value to the data-set
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// or overwrites the oldest if full.
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void RunningMedian::add(float value)
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{
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_values[_index++] = value;
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if (_index >= _size) _index = 0; // wrap around
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if (_count < _size) _count++;
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_sorted = false;
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}
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float RunningMedian::getMedian()
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{
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if (_count == 0) return NAN;
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if (_sorted == false) sort();
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if (_count & 0x01) // is it odd sized?
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{
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return _values[_sortIdx[_count / 2]];
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}
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return (_values[_sortIdx[_count / 2]] + _values[_sortIdx[_count / 2 - 1]]) / 2;
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}
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float RunningMedian::getQuantile(float quantile)
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{
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if (_count == 0) return NAN;
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if ((quantile < 0) || (quantile > 1)) return NAN;
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if (_sorted == false) sort();
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const float index = (_count - 1) * quantile;
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const uint8_t lo = floor(index);
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const uint8_t hi = ceil(index);
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const float qs = _values[_sortIdx[lo]];
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const float h = (index - lo);
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return (1.0 - h) * qs + h * _values[_sortIdx[hi]];
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}
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float RunningMedian::getAverage()
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{
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if (_count == 0) return NAN;
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float sum = 0;
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for (uint8_t i = 0; i < _count; i++)
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{
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sum += _values[i];
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}
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return sum / _count;
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}
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float RunningMedian::getAverage(uint8_t nMedians)
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{
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if ((_count == 0) || (nMedians == 0)) return NAN;
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// when filling the array for first time
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if (_count < nMedians) nMedians = _count;
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uint8_t start = ((_count - nMedians) / 2);
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uint8_t stop = start + nMedians;
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if (_sorted == false) sort();
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float sum = 0;
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for (uint8_t i = start; i < stop; i++)
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{
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sum += _values[_sortIdx[i]];
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}
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return sum / nMedians;
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}
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// nMedians is the spread, or the middle N
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// this version compensated for bias #22
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float RunningMedian::getMedianAverage(uint8_t nMedians)
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{
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// handle special cases.
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if ((_count == 0) || (nMedians == 0)) return NAN;
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if (_count == 1) return _values[0];
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if (_count == 2) return (_values[0] + _values[1]) * 0.5;
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// nMedians can not be larger than current nr of elements.
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if (_count <= nMedians) return getAverage();
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// _count is at least 3 from here
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// Eliminate the bias when the nMedians would fall slightly
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// to the left or right of the centre.
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// If count and nMedians are not both odd or both even reduce
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// the spread by 1 to make them the same.
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// If nMedians becomes 0 correct this. to 2.
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if ((_count & 0x01) != (nMedians & 0x01))
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{
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--nMedians;
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// nmedians can not become 0
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if (nMedians == 0) nMedians = 2;
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}
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uint8_t start = (_count - nMedians) / 2;
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uint8_t stop = start + nMedians;
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if (_sorted == false) sort();
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float sum = 0;
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for (uint8_t i = start; i < stop; i++)
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{
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sum += _values[_sortIdx[i]];
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}
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return sum / nMedians;
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}
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float RunningMedian::getElement(const uint8_t n)
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{
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if ((_count == 0) || (n >= _count)) return NAN;
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uint8_t pos = _index + n;
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if (pos >= _count) // faster than %
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{
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pos -= _count;
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}
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return _values[pos];
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}
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float RunningMedian::getSortedElement(const uint8_t n)
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{
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if ((_count == 0) || (n >= _count)) return NAN;
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if (_sorted == false) sort();
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return _values[_sortIdx[n]];
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}
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// n can be max <= half the (filled) size
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float RunningMedian::predict(const uint8_t n)
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{
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uint8_t mid = _count / 2;
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if ((_count == 0) || (n >= mid)) return NAN;
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float med = getMedian(); // takes care of sorting !
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if (_count & 0x01) // odd # elements
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{
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return max(med - _values[_sortIdx[mid - n]], _values[_sortIdx[mid + n]] - med);
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}
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// even # elements
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float f1 = (_values[_sortIdx[mid - n]] + _values[_sortIdx[mid - n - 1]]) / 2;
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float f2 = (_values[_sortIdx[mid + n]] + _values[_sortIdx[mid + n - 1]]) / 2;
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return max(med - f1, f2 - med) / 2;
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}
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void RunningMedian::setSearchMode(uint8_t searchMode)
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{
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if (searchMode == 1) _searchMode = 1;
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else _searchMode = 0;
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}
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uint8_t RunningMedian::getSearchMode()
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{
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return _searchMode;
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}
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////////////////////////////////////////////////////////////
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//
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// PRIVATE
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//
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// insertion sort - _searchMode = linear or binary.
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void RunningMedian::sort()
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{
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uint16_t lo = 0;
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uint16_t hi = 0;
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uint16_t mi = 0;
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uint16_t temp = 0;
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for (uint16_t i = 1; i < _count; i++)
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{
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temp = _sortIdx[i];
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float f = _values[temp];
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// handle special case f is smaller than all elements first.
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// only one compare needed, improves linear search too.
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if (f <= _values[_sortIdx[0]])
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{
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hi = 0;
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}
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else
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{
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if (_searchMode == 0)
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{
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hi = i;
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// find insertion point with linear search
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while ((hi > 0) && (f < _values[_sortIdx[hi - 1]]))
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{
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hi--;
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}
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}
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else if (_searchMode == 1)
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{
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// find insertion point with binary search
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lo = 0;
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hi = i;
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// be aware there might be duplicates
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while (hi - lo > 1)
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{
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mi = (lo + hi) / 2;
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if (f < _values[_sortIdx[mi]])
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{
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hi = mi;
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}
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else
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{
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lo = mi;
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}
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}
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}
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}
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// move elements to make space
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uint16_t k = i;
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while (k > hi)
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{
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_sortIdx[k] = _sortIdx[k - 1];
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k--;
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}
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// insert at right spot.
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_sortIdx[k] = temp;
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}
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_sorted = true;
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// // verify sorted
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// for (int i = 0; i < _count; i++)
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// {
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// if (i%5 == 0) Serial.println();
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// Serial.print("\t");
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// Serial.print(_values[_sortIdx[i]]);
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// }
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// Serial.println("\n");
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}
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/*
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split version of pre-0.3.7 sort - bit faster
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void RunningMedian::sort()
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{
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// insertSort
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for (uint16_t i = 1; i < _count; i++)
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{
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uint16_t hi = i;
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uint16_t temp = _sortIdx[hi];
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float f = _values[temp];
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while ((hi > 0) && (f < _values[_sortIdx[hi - 1]]))
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{
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hi--;
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}
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// move elements to make space
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uint16_t k = i;
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while (k > hi)
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{
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_sortIdx[k] = _sortIdx[k - 1];
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k--;
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}
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// insert at right spot.
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_sortIdx[k] = temp;
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}
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_sorted = true;
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// // verify sorted
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// for (int i = 0; i < _count; i++)
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// {
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// if (i%5 == 0) Serial.println();
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// Serial.print("\t");
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// Serial.print(_values[_sortIdx[i]]);
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// }
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// Serial.println("\n");
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}
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*/
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/*
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// straightforward insertion sort - PRE-0.3.7
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void RunningMedian::sort()
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{
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for (uint16_t i = 1; i < _count; i++)
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{
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uint16_t z = i;
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uint16_t temp = _sortIdx[z];
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while ((z > 0) && (_values[temp] < _values[_sortIdx[z - 1]]))
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{
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_sortIdx[z] = _sortIdx[z - 1];
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z--;
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}
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_sortIdx[z] = temp;
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}
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_sorted = true;
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// // verify sorted
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// for (int i = 0; i < _count; i++)
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// {
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// if (i%5 == 0) Serial.println();
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// Serial.print("\t");
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// Serial.print(_values[_sortIdx[i]]);
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// }
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// Serial.println("\n");
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}
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*/
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// -- END OF FILE --
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