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#include "sample_selection.h"
#include <hugin.hpp>
#include "powerlist.h"
#include "random.h"
#include "settings.h"
#include <algorithm>
namespace
{
float pow2(float f)
{
return f*f;
}
}
SampleSelection::SampleSelection(Settings& settings, Random& rand, const PowerList& powerlist)
: settings(settings), rand(rand), powerlist(powerlist)
{
}
void SampleSelection::finalise()
{
last.assign(powerlist.getPowerListItems().size(), 0);
}
const Sample* SampleSelection::get(level_t level, std::size_t pos)
{
const auto& samples = powerlist.getPowerListItems();
if(!samples.size())
{
return nullptr;
}
std::size_t index_opt = 0;
float power_opt{0.f};
float value_opt{std::numeric_limits<float>::max()};
float random_opt = 0.;
float close_opt = 0.;
float diverse_opt = 0.;
const float f_close = 4.*settings.sample_selection_f_close.load();
const float f_diverse = (1./2.)*settings.sample_selection_f_diverse.load();
const float f_random = (1./3.)*settings.sample_selection_f_random.load();
float power_range = powerlist.getMaxPower() - powerlist.getMinPower();
if (power_range == 0.) { power_range = 1.0; }
auto closest_it = std::lower_bound(samples.begin(), samples.end(), level);
std::size_t up_index = std::distance(samples.begin(), closest_it);
std::size_t down_index = (up_index == 0 ? 0 : up_index - 1);
float up_value_lb;
if (up_index < samples.size()) {
auto const close_up = (samples[up_index].power-level)/power_range;
up_value_lb = f_close*pow2(close_up);
}
else {
--up_index;
up_value_lb = std::numeric_limits<float>::max();
}
auto const close_down = (samples[down_index].power-level)/power_range;
float down_value_lb = (up_index != 0 ? f_close*pow2(close_down) : std::numeric_limits<float>::max());
std::size_t count = 0;
do
{
DEBUG(rand, "%d %d", (int)up_index, (int)down_index);
if (up_index == samples.size()-1 && down_index == 0) { break; }
std::size_t current_index;
if (up_value_lb < down_value_lb)
{
current_index = up_index;
if (up_index != samples.size()-1)
{
++up_index;
up_value_lb = f_close*pow2((samples[up_index].power-level)/power_range);
}
else
{
up_value_lb = std::numeric_limits<float>::max();
}
}
else
{
current_index = down_index;
if (down_index != 0)
{
--down_index;
down_value_lb = f_close*pow2((samples[down_index].power-level)/power_range);
}
else
{
down_value_lb = std::numeric_limits<float>::max();
}
}
auto random = rand.floatInRange(0.,1.);
auto close = (samples[current_index].power - level)/power_range;
auto diverse = 1./(1. + (float)(pos - last[current_index])/settings.samplerate);
auto value = f_close*pow2(close) + f_diverse*diverse + f_random*random;
if (value < value_opt)
{
index_opt = current_index;
power_opt = samples[current_index].power;
value_opt = value;
random_opt = random;
close_opt = close;
diverse_opt = diverse;
}
++count;
}
while (up_value_lb <= value_opt || down_value_lb <= value_opt);
DEBUG(rand, "Chose sample with index: %d, value: %f, power %f, random: %f, close: %f, diverse: %f, count: %d", (int)index_opt, value_opt, power_opt, random_opt, close_opt, diverse_opt, (int)count);
last[index_opt] = pos;
return samples[index_opt].sample;
}
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