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/*! \internal \file
 * \brief Leap-Frog tests runners.
 *
 * Declares test runner class for Leap-Frog algorithm. The test runners abstract
 * class is used to unify the interfaces for CPU and GPU implementations of the
 * Leap-Frog algorithm. This allows to run the same test on the same data using
 * different implementations of the parent class, that inherit its interfaces.
 *
 * \author Artem Zhmurov <zhmurov@gmail.com>
 * \ingroup module_mdlib
 */
#ifndef GMX_MDLIB_TESTS_LEAPFROGTESTRUNNERS_H
#define GMX_MDLIB_TESTS_LEAPFROGTESTRUNNERS_H

#include "config.h"

#include "gromacs/math/vec.h"

#include "testutils/test_device.h"

#include "leapfrogtestdata.h"

/*
 * LeapFrog is available with CUDA and SYCL.
 */
#define GPU_LEAPFROG_SUPPORTED (GMX_GPU_CUDA || GMX_GPU_SYCL)

namespace gmx
{
namespace test
{

/* \brief LeapFrog integrator test runner interface.
 *
 * Wraps the actual implementation of LeapFrog algorithm into common interface.
 */
class ILeapFrogTestRunner
{
public:
    //! Virtual destructor
    virtual ~ILeapFrogTestRunner() {}
    /*! \brief The abstract function that runs the integrator for a given number of steps.
     *
     * Should be overriden.
     *
     * \param[in]     testData  Data needed for the integrator
     * \param[in]     numSteps  Total number of steps to run integration for.
     */
    virtual void integrate(LeapFrogTestData* testData, int numSteps) = 0;

    /*! \brief Get the human-friendly description of hardware used by the runner.
     *
     * \returns String with description of the hardware.
     */
    virtual std::string hardwareDescription() = 0;
};

// Runner for the CPU version of Leap-Frog.
class LeapFrogHostTestRunner : public ILeapFrogTestRunner
{
public:
    //! Constructor.
    LeapFrogHostTestRunner() {}
    /*! \brief Integrate on the CPU for a given number of steps.
     *
     * Will update the test data with the integration result.
     *
     * \param[in]     testData  Data needed for the integrator
     * \param[in]     numSteps  Total number of steps to run integration for.
     */
    void integrate(LeapFrogTestData* testData, int numSteps) override;
    /*! \brief Get the hardware description
     *
     * \returns "CPU" string.
     */
    std::string hardwareDescription() override { return "CPU"; }
};

// Runner for the CPU version of Leap-Frog.
class LeapFrogDeviceTestRunner : public ILeapFrogTestRunner
{
public:
    /*! \brief Constructor. Keeps a copy of the hardware context.
     *
     * \param[in] testDevice The device hardware context to be used by the runner.
     */
    LeapFrogDeviceTestRunner(const TestDevice& testDevice) : testDevice_(testDevice) {}
    /*! \brief Integrate on the GPU for a given number of steps.
     *
     * Copies data from CPU to GPU, integrates the equation of motion
     * for requested number of steps using Leap-Frog algorithm, copies
     * the result back.
     *
     * \param[in]     testData  Data needed for the integrator
     * \param[in]     numSteps  Total number of steps to run integration for.
     */
    void integrate(LeapFrogTestData* testData, int numSteps) override;
    /*! \brief Get the hardware description
     *
     * \returns A string with GPU description.
     */
    std::string hardwareDescription() override { return testDevice_.description(); }

private:
    //! Test device to be used in the runner.
    const TestDevice& testDevice_;
};

} // namespace test
} // namespace gmx

#endif // GMX_MDLIB_TESTS_LEAPFROGTESTRUNNERS_H
