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Reference

Environment Variables

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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:

VariableRequiredDefaultDescription
NGC_API_KEYYes (for NGC access)—NGC authentication key used to access the NIM container. The default MACE-MPA-0 checkpoint is downloaded separately from Hugging Face.

Configuration Variables

Use the following variables to configure the NIM:

VariableTypeDefaultDescription
ALCHEMI_NIM_MODEL_TYPEstring"mace"Model architecture: mace, aimnet2, or tensornet. Use ALCHEMI_NIM_MODEL_PATH to select the checkpoint.
ALCHEMI_NIM_MODEL_PATHstringnullPath to the model file or directory inside the container.
ALCHEMI_NIM_PBCbooltrueBackend 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_SIZEintnullFixed batch size (null enables automatic estimation at startup).
ALCHEMI_NIM_BATCH_SIZE_ESTIMATE_DATAstring"omat24"Dataset used for automatic batch-size estimation: omat24, omol25, or omc25.
ALCHEMI_NIM_BGR_OPTTOLfloat0.005Force tolerance (eV/Å). Can be overridden per request.
ALCHEMI_NIM_BGR_MAX_STEPSint2000Backend-wide maximum optimization steps, set at startup.
ALCHEMI_NIM_BGR_CELLOPTboolfalseEnable cell optimization. Can be overridden per request.
ALCHEMI_NIM_BGR_OPTTOL_PRESSUREfloat0.5Pressure tolerance (kBar) for cell optimization. Can be overridden per request.
ALCHEMI_NIM_BGR_OPTIMIZER_PRESETstring"materials"Optimizer preset: materials or molecules.
ALCHEMI_NIM_DFTD3_ENABLEDboolfalseEnable DFT-D3(BJ) dispersion correction.
ALCHEMI_NIM_DFTD3_PARAMstring (JSON)nullJSON string containing custom DFT-D3(BJ) parameters. Custom models require a1, a2, and s8. Refer to Configuration for details.

Container Runtime Variables

Use the following variables to configure the container runtime:

VariableRequiredDefaultDescription
NIM_HTTP_API_PORTNo8000HTTP port for the inference API.
ALCHEMI_NIM_DISABLE_MODEL_DOWNLOADNofalseWhether 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.

For launch examples, refer to Quickstart Guide, Custom Models, and Tuning Parameters.