--- /dev/null
+/*
+ * This file is part of the GROMACS molecular simulation package.
+ *
+ * Copyright (c) 2020,2021, by the GROMACS development team, led by
+ * Mark Abraham, David van der Spoel, Berk Hess, and Erik Lindahl,
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+/*! \internal \file
+ *
+ * \brief Implements Leap-Frog using SYCL
+ *
+ * This file contains SYCL implementation of back-end specific code for Leap-Frog.
+ *
+ * \author Artem Zhmurov <zhmurov@gmail.com>
+ * \author Andrey Alekseenko <al42and@gmail.com>
+ *
+ * \ingroup module_mdlib
+ */
+#include "gmxpre.h"
+
+#include "leapfrog_gpu_internal.h"
+
+#include "gromacs/gpu_utils/devicebuffer.h"
+#include "gromacs/gpu_utils/gmxsycl.h"
+#include "gromacs/math/vec.h"
+#include "gromacs/mdlib/leapfrog_gpu.h"
+#include "gromacs/mdtypes/group.h"
+#include "gromacs/utility/arrayref.h"
+#include "gromacs/utility/fatalerror.h"
+#include "gromacs/utility/template_mp.h"
+
+namespace gmx
+{
+
+using cl::sycl::access::mode;
+
+/*! \brief Main kernel for the Leap-Frog integrator.
+ *
+ * The coordinates and velocities are updated on the GPU. Also saves the intermediate values of the coordinates for
+ * further use in constraints.
+ *
+ * Each GPU thread works with a single particle.
+ *
+ * \tparam numTempScaleValues The number of different T-couple values.
+ * \tparam velocityScaling Type of the Parrinello-Rahman velocity rescaling.
+ * \param cgh SYCL's command group handler.
+ * \param[in,out] a_x Coordinates to update upon integration.
+ * \param[out] a_xp A copy of the coordinates before the integration (for constraints).
+ * \param[in,out] a_v Velocities to update.
+ * \param[in] a_f Atomic forces.
+ * \param[in] a_inverseMasses Reciprocal masses.
+ * \param[in] dt Timestep.
+ * \param[in] a_lambdas Temperature scaling factors (one per group).
+ * \param[in] a_tempScaleGroups Mapping of atoms into groups.
+ * \param[in] prVelocityScalingMatrixDiagonal Diagonal elements of Parrinello-Rahman velocity scaling matrix
+ */
+template<NumTempScaleValues numTempScaleValues, VelocityScalingType velocityScaling>
+auto leapFrogKernel(
+ cl::sycl::handler& cgh,
+ DeviceAccessor<Float3, mode::read_write> a_x,
+ DeviceAccessor<Float3, mode::discard_write> a_xp,
+ DeviceAccessor<Float3, mode::read_write> a_v,
+ DeviceAccessor<Float3, mode::read> a_f,
+ DeviceAccessor<float, mode::read> a_inverseMasses,
+ float dt,
+ OptionalAccessor<float, mode::read, numTempScaleValues != NumTempScaleValues::None> a_lambdas,
+ OptionalAccessor<unsigned short, mode::read, numTempScaleValues == NumTempScaleValues::Multiple> a_tempScaleGroups,
+ Float3 prVelocityScalingMatrixDiagonal)
+{
+ cgh.require(a_x);
+ cgh.require(a_xp);
+ cgh.require(a_v);
+ cgh.require(a_f);
+ cgh.require(a_inverseMasses);
+ if constexpr (numTempScaleValues != NumTempScaleValues::None)
+ {
+ cgh.require(a_lambdas);
+ }
+ if constexpr (numTempScaleValues == NumTempScaleValues::Multiple)
+ {
+ cgh.require(a_tempScaleGroups);
+ }
+
+ return [=](cl::sycl::id<1> itemIdx) {
+ const Float3 x = a_x[itemIdx];
+ const Float3 v = a_v[itemIdx];
+ const Float3 f = a_f[itemIdx];
+ const float im = a_inverseMasses[itemIdx];
+ const float imdt = im * dt;
+
+ // Swapping places for xp and x so that the x will contain the updated coordinates and xp -
+ // the coordinates before update. This should be taken into account when (if) constraints
+ // are applied after the update: x and xp have to be passed to constraints in the 'wrong'
+ // order. See Issue #3727
+ a_xp[itemIdx] = x;
+
+ const float lambda = [=]() {
+ if constexpr (numTempScaleValues == NumTempScaleValues::None)
+ {
+ return 1.0F;
+ }
+ else if constexpr (numTempScaleValues == NumTempScaleValues::Single)
+ {
+ return a_lambdas[0];
+ }
+ else if constexpr (numTempScaleValues == NumTempScaleValues::Multiple)
+ {
+ const int tempScaleGroup = a_tempScaleGroups[itemIdx];
+ return a_lambdas[tempScaleGroup];
+ }
+ }();
+
+ const Float3 prVelocityDelta = [=]() {
+ if constexpr (velocityScaling == VelocityScalingType::Diagonal)
+ {
+ return Float3{ prVelocityScalingMatrixDiagonal[0] * v[0],
+ prVelocityScalingMatrixDiagonal[1] * v[1],
+ prVelocityScalingMatrixDiagonal[2] * v[2] };
+ }
+ else if constexpr (velocityScaling == VelocityScalingType::None)
+ {
+ return Float3{ 0, 0, 0 };
+ }
+ }();
+
+ const Float3 v_new = v * lambda - prVelocityDelta + f * imdt;
+ a_v[itemIdx] = v_new;
+ a_x[itemIdx] = x + v_new * dt;
+ };
+}
+
+// SYCL 1.2.1 requires providing a unique type for a kernel. Should not be needed for SYCL2020.
+template<NumTempScaleValues numTempScaleValues, VelocityScalingType velocityScaling>
+class LeapFrogKernelName;
+
+template<NumTempScaleValues numTempScaleValues, VelocityScalingType velocityScaling, class... Args>
+static cl::sycl::event launchLeapFrogKernel(const DeviceStream& deviceStream, int numAtoms, Args&&... args)
+{
+ // Should not be needed for SYCL2020.
+ using kernelNameType = LeapFrogKernelName<numTempScaleValues, velocityScaling>;
+
+ const cl::sycl::range<1> rangeAllAtoms(numAtoms);
+ cl::sycl::queue q = deviceStream.stream();
+
+ cl::sycl::event e = q.submit([&](cl::sycl::handler& cgh) {
+ auto kernel =
+ leapFrogKernel<numTempScaleValues, velocityScaling>(cgh, std::forward<Args>(args)...);
+ cgh.parallel_for<kernelNameType>(rangeAllAtoms, kernel);
+ });
+
+ return e;
+}
+
+static NumTempScaleValues getTempScalingType(bool doTemperatureScaling, int numTempScaleValues)
+{
+ if (!doTemperatureScaling)
+ {
+ return NumTempScaleValues::None;
+ }
+ else if (numTempScaleValues == 1)
+ {
+ return NumTempScaleValues::Single;
+ }
+ else if (numTempScaleValues > 1)
+ {
+ return NumTempScaleValues::Multiple;
+ }
+ else
+ {
+ gmx_incons("Temperature coupling was requested with no temperature coupling groups.");
+ }
+}
+
+/*! \brief Select templated kernel and launch it. */
+template<class... Args>
+static inline cl::sycl::event launchLeapFrogKernel(NumTempScaleValues tempScalingType,
+ VelocityScalingType prVelocityScalingType,
+ Args&&... args)
+{
+ GMX_ASSERT(prVelocityScalingType == VelocityScalingType::None
+ || prVelocityScalingType == VelocityScalingType::Diagonal,
+ "Only isotropic Parrinello-Rahman pressure coupling is supported.");
+
+ return dispatchTemplatedFunction(
+ [&](auto tempScalingType_, auto prScalingType_) {
+ return launchLeapFrogKernel<tempScalingType_, prScalingType_>(std::forward<Args>(args)...);
+ },
+ tempScalingType,
+ prVelocityScalingType);
+}
+
+void launchLeapFrogKernel(int numAtoms,
+ DeviceBuffer<Float3> d_x,
+ DeviceBuffer<Float3> d_xp,
+ DeviceBuffer<Float3> d_v,
+ const DeviceBuffer<Float3> d_f,
+ const DeviceBuffer<float> d_inverseMasses,
+ const float dt,
+ const bool doTemperatureScaling,
+ const int numTempScaleValues,
+ const DeviceBuffer<unsigned short> d_tempScaleGroups,
+ const DeviceBuffer<float> d_lambdas,
+ const VelocityScalingType prVelocityScalingType,
+ const Float3 prVelocityScalingMatrixDiagonal,
+ const DeviceStream& deviceStream)
+{
+ NumTempScaleValues tempVelocityScalingType =
+ getTempScalingType(doTemperatureScaling, numTempScaleValues);
+
+
+ launchLeapFrogKernel(tempVelocityScalingType,
+ prVelocityScalingType,
+ deviceStream,
+ numAtoms,
+ d_x,
+ d_xp,
+ d_v,
+ d_f,
+ d_inverseMasses,
+ dt,
+ d_lambdas,
+ d_tempScaleGroups,
+ prVelocityScalingMatrixDiagonal);
+}
+
+} // namespace gmx
biod.pnpi.spb.ru / alexxy / gromacs.git / blobdiff