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ipa: rpi: histogram: Add interBinMean()

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Add a new helper function Histogram::interBinMean() that essentially
replaces the existing Histogram::interQuantileMean() logic but working on
bins instead.

Rework the interQuantileMean() to call into interBinMean() with the
appropriate convertion from quatiles to bins.

Signed-off-by: Naushir Patuck <naush@raspberrypi.com>
Reviewed-by: David Plowman <david.plowman@raspberrypi.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
This commit is contained in:
Naushir Patuck 2023-09-15 16:58:40 +01:00 • committed by Jacopo Mondi
parent e5f0846695
commit cd940f7fd3
2 changed files with 16 additions and 8 deletions
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22
src/ipa/rpi/controller/histogram.cpp
View file

@ -45,20 +45,26 @@ double Histogram::quantile(double q, int first, int last) const
return first + frac;
}
double Histogram::interQuantileMean(double qLo, double qHi) const
double Histogram::interBinMean(double binLo, double binHi) const
{
assert(qHi > qLo);
double pLo = quantile(qLo);
double pHi = quantile(qHi, (int)pLo);
assert(binHi > binLo);
double sumBinFreq = 0, cumulFreq = 0;
for (double pNext = floor(pLo) + 1.0; pNext <= ceil(pHi);
pLo = pNext, pNext += 1.0) {
int bin = floor(pLo);
for (double binNext = floor(binLo) + 1.0; binNext <= ceil(binHi);
binLo = binNext, binNext += 1.0) {
int bin = floor(binLo);
double freq = (cumulative_[bin + 1] - cumulative_[bin]) *
(std::min(pNext, pHi) - pLo);
(std::min(binNext, binHi) - binLo);
sumBinFreq += bin * freq;
cumulFreq += freq;
}
/* add 0.5 to give an average for bin mid-points */
return sumBinFreq / cumulFreq + 0.5;
}
double Histogram::interQuantileMean(double qLo, double qHi) const
{
assert(qHi > qLo);
double pLo = quantile(qLo);
double pHi = quantile(qHi, (int)pLo);
return interBinMean(pLo, pHi);
}

2
src/ipa/rpi/controller/histogram.h
View file

@ -38,6 +38,8 @@ public:
uint64_t total() const { return cumulative_[cumulative_.size() - 1]; }
/* Cumulative frequency up to a (fractional) point in a bin. */
uint64_t cumulativeFreq(double bin) const;
/* Return the mean value between two (fractional) bins. */
double interBinMean(double binLo, double binHi) const;
/*
* Return the (fractional) bin of the point q (0 <= q <= 1) through the
* histogram. Optionally provide limits to help.