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

#pragma once

// Restrained refinement's targets on a GPU (CUDA builds only): the RefinementEngine of RefinementXray.h with
// everything per evaluation on the device - the atoms' density (ModelDensityGPU's gather), its transform, the
// symmetry composed in reciprocal space, the likelihood target, the derivative map by the inverse transform
// of the target's derivatives and every atom's gradient read off it, and the geometry restraints. The host
// passes positions in and gets one value and one gradient per atom back.

#include <memory>

#include "RefinementXray.h"

// The engine for refining `model` against `refl` on `device`, or null where the GPU cannot take this case (an
// atom's box wider than the cell, too many symmetry operators) or its memory is over `budget` bytes.
// `b_max`: the largest B an atom may reach, which the gather's reserve is sized for. Throws JFJochException on a
// CUDA failure. `nthreads`: the host threads that work out the atoms' densities.
std::unique_ptr<RefinementEngine> MakeRefinementEngineGPU(int device, const gemmi::UnitCell &cell,
                                                          const gemmi::SpaceGroup &sg, double d_min,
                                                          const RefinementReflections &refl,
                                                          const gemmi::Model &model, double b_max, size_t budget,
                                                          size_t *device_bytes = nullptr, size_t nthreads = 1);