To use YACS in your project, you first create a project config
file, typically called config.py
. This file is the one-stop
reference point for all configurable options. It should be very
well documented and provide sensible defaults for all options.
See example for code that uses YACS or keep reading below.
# my_project/config.py
from yacs.config import CfgNode as CN
_C = CN()
_C.SYSTEM = CN()
# Number of GPUS to use in the experiment
_C.SYSTEM.NUM_GPUS = 8
# Number of workers for doing things
_C.SYSTEM.NUM_WORKERS = 4
_C.TRAIN = CN()
# A very important hyperparameter
_C.TRAIN.HYPERPARAMETER_1 = 0.1
# The all important scales for the stuff
_C.TRAIN.SCALES = (2, 4, 8, 16)
# Exporting as cfg is a nice convention
cfg = _C
Next, you'll create YAML configuration files; typically you'll make one for each experiment. Each configuration file only overrides the options that are changing in that experiment.
# my_project/experiment.yaml
SYSTEM:
NUM_GPUS: 2
TRAIN:
SCALES: (1, 2)
Finally, you'll have your actual project code that uses the config
system. After any initial setup it's a good idea to freeze it to
prevent further modification by calling the freeze()
method. As
illustrated below, the config options can either be used a global
set of options by importing cfg
and accessing it directly, or
the cfg
can be copied and passed as an argument.
# my_project/main.py
import pprint
import my_project
from config import cfg
if __name__ == "__main__":
cfg.merge_from_file("experiment.yaml")
cfg.freeze()
pprint.pprint(cfg)
# Example of using the cfg as global access to options
if cfg.SYSTEM.NUM_GPUS > 0:
my_project.setup_multi_gpu_support()
# Example of using a (non-global) copy of the config
model = my_project.create_model(cfg.clone())
TODO:
- document command line overrides
- give usual tips