// SPDX-FileCopyrightText: 2026 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#pragma once

#include <utility>
#include <vector>

// Serial stills given a cell: which frames belong to that crystal. A sample can hold two crystal forms
// (a polymorph, a different hydration state), and a known-cell indexer fits both to the given cell's
// orientation search - the refined cells then fall into two volume populations, and merging both mixes
// two structures. The frames kept are the population the given cell sits in: the peak of the histogram
// of v / v_given - 1 nearest to 0, out to the valley on either side that separates it from another
// population. The histogram bin follows the spread of the data, so neither the
// width of a population nor its distance to the next is a fixed number. A run with one population has
// no such valley and keeps every frame.
//
// relative_volume: v / v_given - 1 per indexed frame. Returns the [low, high] range of it to keep.
std::pair<double, double> GivenCellPopulation(const std::vector<double> &relative_volume);