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38 /*! \libinternal \file
40 * \brief This file contains function declarations necessary for
41 * computing energies and forces for the PME long-ranged part (Coulomb
44 * \author Berk Hess <hess@kth.se>
46 * \ingroup module_ewald
49 #ifndef GMX_EWALD_PME_H
50 #define GMX_EWALD_PME_H
55 #include "gromacs/gpu_utils/devicebuffer_datatype.h"
56 #include "gromacs/gpu_utils/gpu_macros.h"
57 #include "gromacs/math/vectypes.h"
58 #include "gromacs/utility/real.h"
65 struct gmx_wallclock_gpu_pme_t;
66 struct gmx_enerdata_t;
74 enum class GpuTaskCompletion;
76 class GpuEventSynchronizer;
78 /*! \brief Hack to selectively enable some parts of PME during unit testing.
80 * Set to \c false by default. If any of the tests sets it to \c true, it will
81 * make the compatibility check consider PME to be supported in SYCL builds.
83 * Currently we don't have proper PME implementation with SYCL, but we still want
84 * to run tests for some of the kernels.
86 * \todo Remove after #3927 is done and PME is fully enabled in SYCL builds.
88 extern bool g_allowPmeWithSyclForTesting;
94 class ForceWithVirial;
96 enum class PinningPolicy : int;
99 /*! \libinternal \brief Class for managing usage of separate PME-only ranks
101 * Used for checking if some parts of the code could not use PME-only ranks
104 class SeparatePmeRanksPermitted
107 //! Disables PME ranks permitted flag with a reason
108 void disablePmeRanks(const std::string& reason);
109 //! Return status of PME ranks usage
110 bool permitSeparatePmeRanks() const;
111 //! Returns all reasons, for not using PME ranks
112 std::string reasonsWhyDisabled() const;
115 //! Flag that informs whether simualtion could use dedicated PME ranks
116 bool permitSeparatePmeRanks_ = true;
117 //! Storage for all reasons, why PME ranks could not be used
118 std::vector<std::string> reasons_;
125 GMX_SUM_GRID_FORWARD,
126 GMX_SUM_GRID_BACKWARD
129 /*! \brief Possible PME codepaths on a rank.
130 * \todo: make this enum class with gmx_pme_t C++ refactoring
132 enum class PmeRunMode
134 None, //!< No PME task is done
135 CPU, //!< Whole PME computation is done on CPU
136 GPU, //!< Whole PME computation is done on GPU
137 Mixed, //!< Mixed mode: only spread and gather run on GPU; FFT and solving are done on CPU.
140 /*! \brief Return the smallest allowed PME grid size for \p pmeOrder */
141 int minimalPmeGridSize(int pmeOrder);
143 //! Return whether the grid of \c pme is identical to \c grid_size.
144 bool gmx_pme_grid_matches(const gmx_pme_t& pme, const ivec grid_size);
146 /*! \brief Check restrictions on pme_order and the PME grid nkx,nky,nkz.
148 * With errorsAreFatal=true, an exception or fatal error is generated
149 * on violation of restrictions.
150 * With errorsAreFatal=false, false is returned on violation of restrictions.
151 * When all restrictions are obeyed, true is returned.
152 * Argument useThreads tells if any MPI rank doing PME uses more than 1 threads.
153 * If at calling useThreads is unknown, pass true for conservative checking.
155 * The PME GPU restrictions are checked separately during pme_gpu_init().
157 bool gmx_pme_check_restrictions(int pme_order,
161 int numPmeDomainsAlongX,
163 bool errorsAreFatal);
165 /*! \brief Construct PME data
167 * \throws gmx::InconsistentInputError if input grid sizes/PME order are inconsistent.
168 * \returns Pointer to newly allocated and initialized PME data.
170 * \todo We should evolve something like a \c GpuManager that holds \c
171 * DeviceInformation* and \c PmeGpuProgram* and perhaps other
172 * related things whose lifetime can/should exceed that of a task (or
173 * perhaps task manager). See Issue #2522.
175 gmx_pme_t* gmx_pme_init(const t_commrec* cr,
176 const NumPmeDomains& numPmeDomains,
177 const t_inputrec* ir,
178 gmx_bool bFreeEnergy_q,
179 gmx_bool bFreeEnergy_lj,
180 gmx_bool bReproducible,
186 const DeviceContext* deviceContext,
187 const DeviceStream* deviceStream,
188 const PmeGpuProgram* pmeGpuProgram,
189 const gmx::MDLogger& mdlog);
191 /*! \brief As gmx_pme_init, but takes most settings, except the grid/Ewald coefficients, from
192 * pme_src. This is only called when the PME cut-off/grid size changes.
194 void gmx_pme_reinit(gmx_pme_t** pmedata,
197 const t_inputrec* ir,
198 const ivec grid_size,
202 /*! \brief Destroys the PME data structure.*/
203 void gmx_pme_destroy(gmx_pme_t* pme);
205 /*! \brief Do a PME calculation on a CPU for the long range electrostatics and/or LJ.
207 * Computes the PME forces and the energy and viral, when requested,
208 * for all atoms in \p coordinates. Forces, when requested, are added
209 * to the buffer \p forces, which is allowed to contain more elements
210 * than the number of elements in \p coordinates.
211 * The meaning of \p flags is defined above, and determines which
212 * parts of the calculation are performed.
214 * \return 0 indicates all well, non zero is an error code.
216 int gmx_pme_do(struct gmx_pme_t* pme,
217 gmx::ArrayRef<const gmx::RVec> coordinates,
218 gmx::ArrayRef<gmx::RVec> forces,
219 gmx::ArrayRef<const real> chargeA,
220 gmx::ArrayRef<const real> chargeB,
221 gmx::ArrayRef<const real> c6A,
222 gmx::ArrayRef<const real> c6B,
223 gmx::ArrayRef<const real> sigmaA,
224 gmx::ArrayRef<const real> sigmaB,
230 gmx_wallcycle* wcycle,
239 const gmx::StepWorkload& stepWork);
241 /*! \brief Calculate the PME grid energy V for n charges.
243 * The potential (found in \p pme) must have been found already with a
244 * call to gmx_pme_do(). Note that the charges are not spread on the grid in the
245 * pme struct. Currently does not work in parallel or with free
248 real gmx_pme_calc_energy(gmx_pme_t* pme, gmx::ArrayRef<const gmx::RVec> x, gmx::ArrayRef<const real> q);
251 * This function updates the local atom data on GPU after DD (charges, coordinates, etc.).
252 * TODO: it should update the PME CPU atom data as well.
253 * (currently PME CPU call gmx_pme_do() gets passed the input pointers for each computation).
255 * \param[in,out] pme The PME structure.
256 * \param[in] numAtoms The number of particles.
257 * \param[in] chargesA The pointer to the array of particle charges in the normal state or FEP
258 * state A. Can be nullptr if PME is not performed on the GPU.
259 * \param[in] chargesB The pointer to the array of particle charges in state B. Only used if
260 * charges are perturbed and can otherwise be nullptr.
262 void gmx_pme_reinit_atoms(gmx_pme_t* pme,
264 gmx::ArrayRef<const real> chargesA,
265 gmx::ArrayRef<const real> chargesB);
267 /* A block of PME GPU functions */
269 /*! \brief Checks whether the GROMACS build allows to run PME on GPU.
270 * TODO: this partly duplicates an internal PME assert function
271 * pme_gpu_check_restrictions(), except that works with a
272 * formed gmx_pme_t structure. Should that one go away/work with inputrec?
274 * \param[out] error If non-null, the error message when PME is not supported on GPU.
276 * \returns true if PME can run on GPU on this build, false otherwise.
278 bool pme_gpu_supports_build(std::string* error);
280 /*! \brief Checks whether the detected (GPU) hardware allows to run PME on GPU.
282 * \param[in] hwinfo Information about the detected hardware
283 * \param[out] error If non-null, the error message when PME is not supported on GPU.
285 * \returns true if PME can run on GPU on this build, false otherwise.
287 bool pme_gpu_supports_hardware(const gmx_hw_info_t& hwinfo, std::string* error);
289 /*! \brief Checks whether the input system allows to run PME on GPU.
290 * TODO: this partly duplicates an internal PME assert function
291 * pme_gpu_check_restrictions(), except that works with a
292 * formed gmx_pme_t structure. Should that one go away/work with inputrec?
294 * \param[in] ir Input system.
295 * \param[out] error If non-null, the error message if the input is not supported on GPU.
297 * \returns true if PME can run on GPU with this input, false otherwise.
299 bool pme_gpu_supports_input(const t_inputrec& ir, std::string* error);
302 * Returns the active PME codepath (CPU, GPU, mixed).
303 * \todo This is a rather static data that should be managed by the higher level task scheduler.
305 * \param[in] pme The PME data structure.
306 * \returns active PME codepath.
308 PmeRunMode pme_run_mode(const gmx_pme_t* pme);
310 /*! \libinternal \brief
311 * Return the pinning policy appropriate for this build configuration
312 * for relevant buffers used for PME task on this rank (e.g. running
314 gmx::PinningPolicy pme_get_pinning_policy();
317 * Tells if PME is enabled to run on GPU (not necessarily active at the moment).
318 * \todo This is a rather static data that should be managed by the hardware assignment manager.
319 * For now, it is synonymous with the active PME codepath (in the absence of dynamic switching).
321 * \param[in] pme The PME data structure.
322 * \returns true if PME can run on GPU, false otherwise.
324 inline bool pme_gpu_task_enabled(const gmx_pme_t* pme)
326 return (pme != nullptr) && (pme_run_mode(pme) != PmeRunMode::CPU);
329 /*! \brief Returns the block size requirement
331 * The GPU version of PME requires that the coordinates array have a
332 * size divisible by the returned number.
334 * \param[in] pme The PME data structure.
336 GPU_FUNC_QUALIFIER int pme_gpu_get_block_size(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme))
337 GPU_FUNC_TERM_WITH_RETURN(0);
339 // The following functions are all the PME GPU entry points,
340 // currently inlining to nothing on non-CUDA builds.
343 * Resets the PME GPU timings. To be called at the reset step.
345 * \param[in] pme The PME structure.
347 GPU_FUNC_QUALIFIER void pme_gpu_reset_timings(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme)) GPU_FUNC_TERM;
350 * Copies the PME GPU timings to the gmx_wallclock_gpu_pme_t structure (for log output). To be called at the run end.
352 * \param[in] pme The PME structure.
353 * \param[in] timings The gmx_wallclock_gpu_pme_t structure.
355 GPU_FUNC_QUALIFIER void pme_gpu_get_timings(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
356 gmx_wallclock_gpu_pme_t* GPU_FUNC_ARGUMENT(timings)) GPU_FUNC_TERM;
358 /* The main PME GPU functions */
361 * Prepares PME on GPU computation (updating the box if needed)
362 * \param[in] pme The PME data structure.
363 * \param[in] box The unit cell box.
364 * \param[in] wcycle The wallclock counter.
365 * \param[in] stepWork The required work for this simulation step
367 GPU_FUNC_QUALIFIER void pme_gpu_prepare_computation(gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
368 const matrix GPU_FUNC_ARGUMENT(box),
369 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle),
370 const gmx::StepWorkload& GPU_FUNC_ARGUMENT(stepWork)) GPU_FUNC_TERM;
373 * Launches first stage of PME on GPU - spreading kernel.
375 * \param[in] pme The PME data structure.
376 * \param[in] xReadyOnDevice Event synchronizer indicating that the coordinates
377 * are ready in the device memory; nullptr allowed only on separate PME ranks.
378 * \param[in] wcycle The wallclock counter.
379 * \param[in] lambdaQ The Coulomb lambda of the current state of the
380 * system. Only used if FEP of Coulomb is active.
382 GPU_FUNC_QUALIFIER void pme_gpu_launch_spread(gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
383 GpuEventSynchronizer* GPU_FUNC_ARGUMENT(xReadyOnDevice),
384 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle),
385 real GPU_FUNC_ARGUMENT(lambdaQ)) GPU_FUNC_TERM;
388 * Launches middle stages of PME (FFT R2C, solving, FFT C2R) either on GPU or on CPU, depending on the run mode.
390 * \param[in] pme The PME data structure.
391 * \param[in] wcycle The wallclock counter.
392 * \param[in] stepWork The required work for this simulation step
394 GPU_FUNC_QUALIFIER void
395 pme_gpu_launch_complex_transforms(gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
396 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle),
397 const gmx::StepWorkload& GPU_FUNC_ARGUMENT(stepWork)) GPU_FUNC_TERM;
400 * Launches last stage of PME on GPU - force gathering and D2H force transfer.
402 * \param[in] pme The PME data structure.
403 * \param[in] wcycle The wallclock counter.
404 * \param[in] lambdaQ The Coulomb lambda to use when calculating the results.
406 GPU_FUNC_QUALIFIER void pme_gpu_launch_gather(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
407 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle),
408 real GPU_FUNC_ARGUMENT(lambdaQ)) GPU_FUNC_TERM;
411 * Attempts to complete PME GPU tasks.
413 * The \p completionKind argument controls whether the function blocks until all
414 * PME GPU tasks enqueued completed (as pme_gpu_wait_finish_task() does) or only
415 * checks and returns immediately if they did not.
416 * When blocking or the tasks have completed it also gets the output forces
417 * by assigning the ArrayRef to the \p forces pointer passed in.
418 * Virial/energy are also outputs if they were to be computed.
420 * \param[in] pme The PME data structure.
421 * \param[in] stepWork The required work for this simulation step
422 * \param[in] wcycle The wallclock counter.
423 * \param[out] forceWithVirial The output force and virial
424 * \param[out] enerd The output energies
425 * \param[in] lambdaQ The Coulomb lambda to use when calculating the results.
426 * \param[in] completionKind Indicates whether PME task completion should only be checked rather
428 * \returns True if the PME GPU tasks have completed
430 GPU_FUNC_QUALIFIER bool pme_gpu_try_finish_task(gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
431 const gmx::StepWorkload& GPU_FUNC_ARGUMENT(stepWork),
432 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle),
433 gmx::ForceWithVirial* GPU_FUNC_ARGUMENT(forceWithVirial),
434 gmx_enerdata_t* GPU_FUNC_ARGUMENT(enerd),
435 real GPU_FUNC_ARGUMENT(lambdaQ),
436 GpuTaskCompletion GPU_FUNC_ARGUMENT(completionKind))
437 GPU_FUNC_TERM_WITH_RETURN(false);
440 * Blocks until PME GPU tasks are completed, and gets the output forces and virial/energy
441 * (if they were to be computed).
443 * \param[in] pme The PME data structure.
444 * \param[in] stepWork The required work for this simulation step
445 * \param[in] wcycle The wallclock counter.
446 * \param[out] forceWithVirial The output force and virial
447 * \param[out] enerd The output energies
448 * \param[in] lambdaQ The Coulomb lambda to use when calculating the results.
450 GPU_FUNC_QUALIFIER void pme_gpu_wait_and_reduce(gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
451 const gmx::StepWorkload& GPU_FUNC_ARGUMENT(stepWork),
452 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle),
453 gmx::ForceWithVirial* GPU_FUNC_ARGUMENT(forceWithVirial),
454 gmx_enerdata_t* GPU_FUNC_ARGUMENT(enerd),
455 real GPU_FUNC_ARGUMENT(lambdaQ)) GPU_FUNC_TERM;
458 * The PME GPU reinitialization function that is called both at the end of any PME computation and on any load balancing.
460 * Clears the internal grid and energy/virial buffers; it is not safe to start
461 * the PME computation without calling this.
462 * Note that unlike in the nbnxn module, the force buffer does not need clearing.
464 * \todo Rename this function to *clear* -- it clearly only does output resetting
465 * and we should be clear about what the function does..
467 * \param[in] pme The PME data structure.
468 * \param[in] wcycle The wallclock counter.
470 GPU_FUNC_QUALIFIER void pme_gpu_reinit_computation(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
471 gmx_wallcycle* GPU_FUNC_ARGUMENT(wcycle)) GPU_FUNC_TERM;
473 /*! \brief Set pointer to device copy of coordinate data.
474 * \param[in] pme The PME data structure.
475 * \param[in] d_x The pointer to the positions buffer to be set
477 GPU_FUNC_QUALIFIER void pme_gpu_set_device_x(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme),
478 DeviceBuffer<gmx::RVec> GPU_FUNC_ARGUMENT(d_x)) GPU_FUNC_TERM;
480 /*! \brief Get pointer to device copy of force data.
481 * \param[in] pme The PME data structure.
482 * \returns Pointer to force data
484 GPU_FUNC_QUALIFIER DeviceBuffer<gmx::RVec> pme_gpu_get_device_f(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme))
485 GPU_FUNC_TERM_WITH_RETURN(DeviceBuffer<gmx::RVec>{});
487 /*! \brief Get pointer to the device synchronizer object that allows syncing on PME force calculation completion
488 * \param[in] pme The PME data structure.
489 * \returns Pointer to synchronizer
491 GPU_FUNC_QUALIFIER GpuEventSynchronizer* pme_gpu_get_f_ready_synchronizer(const gmx_pme_t* GPU_FUNC_ARGUMENT(pme))
492 GPU_FUNC_TERM_WITH_RETURN(nullptr);