Jungfraujoch/image_analysis/scale_merge/HKLKey.cpp

// SPDX-FileCopyrightText: 2025 Filip Leonarski, Paul Scherrer Institute <filip.leonarski@psi.ch>
// SPDX-License-Identifier: GPL-3.0-only

#include <cmath>

#include "HKLKey.h"
#include "gemmi/symmetry.hpp"

HKLKey CanonicalHKL(const Reflection &r, bool merge_friedel, const std::optional<gemmi::SpaceGroup> &in_sg) {
    HKLKey key{r.h, r.k, r.l, true};

    if (!in_sg.has_value()) {
        if (!merge_friedel) {
            const HKLKey neg{-r.h, -r.k, -r.l, true};
            if (std::tie(key.h, key.k, key.l) < std::tie(neg.h, neg.k, neg.l)) {
                key.h = -key.h;
                key.k = -key.k;
                key.l = -key.l;
                key.plus = false;
            }
        }
    } else {
        gemmi::SpaceGroup sg = in_sg.value();
        const auto ops = sg.operations();
        const gemmi::ReciprocalAsu asu(&sg);

        const gemmi::Op::Miller in{r.h, r.k, r.l};
        const auto [hkl, sign_plus] = asu.to_asu_sign(in, ops);

        key.h = hkl[0];
        key.k = hkl[1];
        key.l = hkl[2];
        key.plus = merge_friedel ? true : sign_plus;
    }
    return key;
}

bool AcceptReflection(const Reflection &r, double d_min_limit) {
    if (!std::isfinite(r.I))
        return false;
    if (!std::isfinite(r.d) || r.d <= 0.0f)
        return false;
    if (d_min_limit > 0.0 && r.d < d_min_limit)
        return false;
    if (!std::isfinite(r.rlp) || r.rlp == 0.0f)
        return false;
    return true;
}