Organized by GPT-6-Astra. SPONGE 2.0 is under active, iterative development; features, parameters, and documentation may change. Consult the GitHub repository’s docs and skills for the latest version information.

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SinkMeta/meta Input Parameters

This list is derived from META::Initial() in SPONGE/bias/sinkmeta/config/config.cpp and default values in SPONGE/bias/sinkmeta/meta.h.

Parameters (module: meta)

Parameter	Type / Shape	Required	Default (if any)	Meaning / Notes
CV	string list	Yes	None	CV module names used by Meta; determines dimensionality. If missing, META is not initialized.
dip	float	No	0.0	Extra dip term for submarine/sink behavior (adds to bias shift via kB*T).
welltemp_factor	float	No	1e9	Well-tempered bias factor; if > 1 enables well-tempered mode.
Ndim	int	No	CV count	Explicit dimensionality; must match CV list length.
subhill	flag	No	false	Enable sub-hill (Gaussian) behavior. Presence-only (no value read).
kde	int	No	0	Nonzero enables KDE mode and also sets subhill=true. Also switches sigma scaling to 1.414/sigma.
mask	int	No	0	Enable mask mode (n-dim area exit label).
maxforce	float	No	0.1	Edge force criterion for exit label; only read when mask is set.
sink	int	No	0	Nonzero enables negative-hill (sink/submarine) behavior.
sumhill_freq	int	No	0	History frequency for sumhill accumulation (affects Rbias/RCT).
convmeta	int	No	0	ConvolutionMeta flag; also sets do_negative=true.
grw	int	No	0	GRW flag; also sets do_negative=true.
CV_period	float array (ndim)	Yes	None in META	Periodic box length per CV. Always requested in META::Initial().
CV_sigma	float array (ndim)	Yes	None in META	Gaussian width per CV (must be > 0). Stored internally as inverse sigma.
cutoff	float array (ndim)	No	3 * CV_sigma	Neighbor cutoff for lookup and border wall; if present enables do_cutoff.
potential_in_file	string	No	None	Read potential from file; if set, Read_Potential() is called (grid/scatter settings below are bypassed).
scatter_in_file	string	No	None	Read scatter potential from file; sets use_scatter=true, usegrid=false, and calls Read_Potential().
edge_in_file	string	No	sumhill.log	Edge-effect cache file used by EdgeEffect(). If the file exists and matches the expected grid size, SinkMeta reads it directly; otherwise it regenerates and writes to the same path.
scatter	int	No	0	Number of scatter points; if > 0 uses scatter points instead of grid.
CV_minimal	float array (ndim)	Conditionally	None in META	Grid minimum per CV; required when not using potential_in_file or scatter_in_file.
CV_maximum	float array (ndim)	Conditionally	None in META	Grid maximum per CV; must be > CV_minimal. Required when not using potential_in_file or scatter_in_file.
CV_grid	int array (ndim)	Conditionally	None in META	Grid points per CV; must be > 1. Required when not using potential_in_file or scatter_in_file.
height	float	No	1.0	Initial hill height (height_0).
wall_height	float	No	None	Enables border wall and sets border_potential_height.
potential_out_file	string	No	Meta_Potential.txt	Output file name for writing potential.
potential_update_interval	int	No	write_information_interval or 1000	Step interval for writing potential; if <= 0 it is forced to 1000.

Parameters used from other modules / global

Parameter	Scope	Type / Shape	Required	Default (if any)	Meaning / Notes
CV_point	Each CV module	float array (scatter size)	Conditionally	None in META	Scatter point coordinates per CV; read only when scatter > 0.
write_information_interval	Controller	int	No	1000	Global controller interval; used as default for potential_update_interval.

Notes

• If both potential_in_file and scatter_in_file are present, potential_in_file takes precedence (the code uses if/else if).
• CV_sigma is inverted internally; kde mode uses 1.414 / sigma, otherwise 1.0 / sigma.
• Default file names set in code: read_potential_file_name and write_potential_file_name both start as Meta_Potential.txt.