domdec_setup.h File Reference

#include "gromacs/math/vec.h"
#include "gromacs/utility/gmxmpi.h"

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Description

Declares functions for choosing the DD grid setup.

Author

Berk Hess hess@.nosp@m.kth..nosp@m.se

Classes
class	gmx::ArrayRef< typename >
	STL-like interface to a C array of T (or part of a std container of T). More...
struct	DDGridSetup
	Describes the DD grid setup. More...

Functions
real	comm_box_frac (const gmx::IVec &dd_nc, real cutoff, const gmx_ddbox_t &ddbox)
	Returns the volume fraction of the system that is communicated.
gmx::SeparatePmeRanksPermitted	checkForSeparatePmeRanks (const gmx::MDModulesNotifiers &notifiers, const gmx::DomdecOptions &options, int numRanksRequested, bool useGpuForNonbonded, bool useGpuForPme, bool canUseGpuPmeDecomposition)
	Checks for ability to use separate PME ranks. More...
void	checkForValidRankCountRequests (int numRanksRequested, bool usingPme, int numPmeRanksRequested, const gmx::SeparatePmeRanksPermitted &separatePmeRanksPermitted, bool checkForLargePrimeFactors)
	Checks that requests for PP and PME ranks honor basic expectations. More...
real	getDDGridSetupCellSizeLimit (const gmx::MDLogger &mdlog, bool bDynLoadBal, real dlb_scale, const t_inputrec &ir, real systemInfoCellSizeLimit, int numRanksRequested)
	Return the minimum cell size (in nm) required for DD.
DDGridSetup	getDDGridSetup (const gmx::MDLogger &mdlog, DDRole ddRole, MPI_Comm communicator, int numRanksRequested, const gmx::DomdecOptions &options, const DDSettings &ddSettings, const DDSystemInfo &systemInfo, real cellSizeLimit, const gmx_mtop_t &mtop, const t_inputrec &ir, const gmx::SeparatePmeRanksPermitted &separatePmeRanksPermitted, const matrix box, gmx::ArrayRef< const gmx::RVec > xGlobal, gmx_ddbox_t *ddbox)
	Determines the DD grid setup. More...

Function Documentation

gmx::SeparatePmeRanksPermitted checkForSeparatePmeRanks	(	const gmx::MDModulesNotifiers &	notifiers,
		const gmx::DomdecOptions &	options,
		int	numRanksRequested,
		bool	useGpuForNonbonded,
		bool	useGpuForPme,
		bool	canUseGpuPmeDecomposition
	)

Checks for ability to use separate PME ranks.

Disables automatic usage if: some MDModule could not use separate PME ranks, GPU setup is not compatible with separate PME ranks, user provided explicit DD grid or total number of ranks is not large enough to use PME ranks

void checkForValidRankCountRequests	(	int	numRanksRequested,
		bool	usingPme,
		int	numPmeRanksRequested,
		const gmx::SeparatePmeRanksPermitted &	separatePmeRanksPermitted,
		bool	checkForLargePrimeFactors
	)

Checks that requests for PP and PME ranks honor basic expectations.

Issues a fatal error if there are more PME ranks than PP, if the count of PP ranks has a prime factor that is too large to be likely to have good performance or PME-only ranks could not be used, but requested with -npme > 0

DDGridSetup getDDGridSetup	(	const gmx::MDLogger &	mdlog,
		DDRole	ddRole,
		MPI_Comm	communicator,
		int	numRanksRequested,
		const gmx::DomdecOptions &	options,
		const DDSettings &	ddSettings,
		const DDSystemInfo &	systemInfo,
		real	cellSizeLimit,
		const gmx_mtop_t &	mtop,
		const t_inputrec &	ir,
		const gmx::SeparatePmeRanksPermitted &	separatePmeRanksPermitted,
		const matrix	box,
		gmx::ArrayRef< const gmx::RVec >	xGlobal,
		gmx_ddbox_t *	ddbox
	)

Determines the DD grid setup.

Either implements settings required by the user, or otherwise chooses estimated optimal number of separate PME ranks and DD grid cell setup, DD cell size limits, and the initial ddbox.