Checkpointing

ActivitySim provides a checkpointing mechanism, whereby the content of data tables can be stored to disk in an intermediate state. This intermediate state can subsequently be restored from disk, setting up the data tables to resume simulation from that point forward.

There are currently two data file formats available for checkpointing:

• HDF5, the longstanding default format for ActivitySim checkpointing, and

• Apache Parquet, added as an option as of ActivitySim version 1.3.

Usage

The operation of automatic checkpointing during an ActivitySim run is controlled via a few values in the top-level settings:

• checkpoint_format controls which checkpoint data file format is used.

• checkpoints controls how frequently checkpoints are written (after every component, after only certain components, or not at all).

For code developers wanting to integrate some aspect of checkpointing into a manual workflow or a new component, the State.checkpoint accessor has most of the relevant methods.

API

GenericCheckpointStore()	Abstract base class defining interface for table storage.
HdfStore(filename[, mode])	Storage interface for HDF5-based table storage.
ParquetStore(directory[, mode, gitignore])	Storage interface for parquet-based table storage.