Environment Variables#

Configure NIM for BGR behavior at container startup using the following environment variables.

Required Variables#

The following variable is required for authenticated access to the NGC container registry:

Variable	Required	Default	Description
`NGC_API_KEY`	Yes (for NGC access)	–	NGC authentication key used to access the NIM container. The default MACE-MPA-0 checkpoint is downloaded separately from Hugging Face.

Use the following variables to configure the NIM:

Variable	Type	Default	Description
`ALCHEMI_NIM_MODEL_TYPE`	string	`"mace"`	Model architecture: `mace`, `aimnet2`, or `tensornet`. Use `ALCHEMI_NIM_MODEL_PATH` to select the checkpoint.
`ALCHEMI_NIM_MODEL_PATH`	string	null	Path to the model file or directory inside the container.
`ALCHEMI_NIM_PBC`	bool	true	Backend PBC mode. When true, every request structure must include `cell`; when false, every structure must omit `cell`. Nested `atoms[].pbc` values do not override this mode.
`ALCHEMI_NIM_BATCH_SIZE`	int	null	Fixed batch size (`null` enables automatic estimation at startup).
`ALCHEMI_NIM_BATCH_SIZE_ESTIMATE_DATA`	string	`"omat24"`	Dataset used for automatic batch-size estimation: `omat24`, `omol25`, or `omc25`.
`ALCHEMI_NIM_BGR_OPTTOL`	float	0.005	Force tolerance (eV/Å). Can be overridden per request.
`ALCHEMI_NIM_BGR_MAX_STEPS`	int	2000	Backend-wide maximum optimization steps, set at startup.
`ALCHEMI_NIM_BGR_CELLOPT`	bool	false	Enable cell optimization. Can be overridden per request.
`ALCHEMI_NIM_BGR_OPTTOL_PRESSURE`	float	0.5	Pressure tolerance (kBar) for cell optimization. Can be overridden per request.
`ALCHEMI_NIM_BGR_OPTIMIZER_PRESET`	string	`"materials"`	Optimizer preset: `materials` or `molecules`.
`ALCHEMI_NIM_DFTD3_ENABLED`	bool	false	Enable DFT-D3(BJ) dispersion correction.
`ALCHEMI_NIM_DFTD3_PARAM`	string (JSON)	null	JSON string containing custom DFT-D3(BJ) parameters. Custom models require `a1`, `a2`, and `s8`. Refer to Configuration for details.

Use the following variables to configure the container runtime:

Variable	Required	Default	Description
`NIM_HTTP_API_PORT`	No	`8000`	HTTP port for the inference API.
`ALCHEMI_NIM_DISABLE_MODEL_DOWNLOAD`	No	false	Whether to disable the automatic startup download of the default MACE-MPA-0 checkpoint from Hugging Face. Set to `true` when mounting a user-provided model.