Habitat-API Configuration

Habitat-API uses Yacs configuration system with the paradigm of your code + a YACS config for experiment E (+ external dependencies + hardware + other nuisance terms ...) = reproducible experiment E. Yacs advantages:

• Checks for type consistency.
• All parameters and default values are searchable in the code.
• A parameter doesn't need to be set always as each parameter has a default value.
• Ability to freeze config to prevent unintended changes.

Config usage

An example of how to merge default config with 2 others configs and overwrite one parameter that could come from the command line:

    merged_config = get_config(
        config_paths=["configs/tasks/pointnav.yaml", 
            "configs/dataset/val.yaml"],
        opts=["ENVIRONMENT.MAX_EPISODE_STEPS", steps_limit]
    )

Config structure

Below is the structure of config used for Habitat:

• Environment
• Task
  • Sensors
  • Measurements
• Simulator
  • Agent
    • Sensors
• Dataset

We use node names (e.g. SENSORS: ['RGB_SENSOR', 'DEPTH_SENSOR']) instead of list of config nodes (e.g. SENSORS: [{TYPE = "HabitatSimDepthSensor", MIN_DEPTH = 0}, ...]) to declare the Sensors attached to an Agent or Measures enabled for the Task . With this approach, it's still easy to overwrite a particular sensor parameter in yaml file without redefining the whole sensor config.

Extending the config

Example of how to extend a config outside of habtiat-api repository. First, we create a config extending the default config in the code and re-use habitat.get_config():

import habitat
import argparse
from typing import List, Optional, Union

_C = habitat.get_config()
_C.defrost()
# Add new parameters to the config
_C.TASK.EPISODE_INFO = habitat.Config()
_C.TASK.EPISODE_INFO.TYPE = "EpisodeInfo"
_C.TASK.EPISODE_INFO.VALUE = 5
_C.TASK.MEASUREMENTS.append("EPISODE_INFO")

# New function returning extended Habitat config that should be used instead
# of habitat.get_config()
def my_get_config(
        config_paths: Optional[Union[List[str], str]] = None,
        opts: Optional[list] = None,
) -> habitat.Config:
    CONFIG_FILE_SEPARATOR = ","
    config = _C.clone()
    if config_paths:
        if isinstance(config_paths, str):
            if CONFIG_FILE_SEPARATOR in config_paths:
                config_paths = config_paths.split(CONFIG_FILE_SEPARATOR)
            else:
                config_paths = [config_paths]

        for config_path in config_paths:
            config.merge_from_file(config_path)

    if opts:
        config.merge_from_list(opts)

    config.freeze()
    return config

def main():
    parser = argparse.ArgumentParser()
    parser.add_argument(
        "--task-config",
        type=str,
        default="configs/tasks/pointnav.yaml,"
                "configs/datasets/pointnav/habitat_test.yaml",
    )
    parser.add_argument(
        "opts",
        default=None,
        nargs=argparse.REMAINDER,
        help="Modify config options from command line",
    )
    args = parser.parse_args()
    config = my_get_config(config_paths=args.task_config, opts=args.opts)
    env = habitat.Env(config)