# Defaults for finetuning with train.py.
#
#
# You must also include a binding for MODEL.
#
# Required to be set:
#
# - MIXTURE_OR_TASK_NAME
# - TASK_FEATURE_LENGTHS
# - TRAIN_STEPS  # includes pretrain steps
# - MODEL_DIR  # automatically set when using xm_launch
# - INITIAL_CHECKPOINT_PATH
#
# When running locally, it needs to be passed in the `gin.MODEL_DIR` flag.
#
# `TRAIN_STEPS` should include pre-training steps, e.g., if pre-trained ckpt
# has 1M steps, TRAIN_STEPS = 1.1M will perform 0.1M fine-tuning steps.
#
# Commonly overridden options:
# - DROPOUT_RATE
# - BATCH_SIZE
# - PjitPartitioner.num_partitions
# - Trainer.num_microbatches
# - USE_CACHED_TASKS: Whether to look for preprocessed SeqIO data, or preprocess
#    on the fly. Most common tasks are cached, hence this is set to True by
#    default.

from __gin__ import dynamic_registration

import __main__ as train_script
import seqio
from t5x import gin_utils
from t5x import partitioning
from t5x import utils
from t5x import trainer

# Must be overridden
MODEL_DIR = %gin.REQUIRED
MIXTURE_OR_TASK_NAME = %gin.REQUIRED
TASK_FEATURE_LENGTHS = %gin.REQUIRED
MIXTURE_OR_TASK_MODULE = %gin.REQUIRED
TRAIN_STEPS = %gin.REQUIRED
INITIAL_CHECKPOINT_PATH = %gin.REQUIRED

# Commonly overridden
DROPOUT_RATE = 0.1
USE_CACHED_TASKS = True
BATCH_SIZE = 128

# Sometimes overridden
EVAL_STEPS = 20

# Convenience overrides.
EVALUATOR_USE_MEMORY_CACHE = True
EVALUATOR_NUM_EXAMPLES = None  # Use all examples in the infer_eval dataset.
JSON_WRITE_N_RESULTS = None  # Write all inferences.
# HW RNG is faster than SW, but has limited determinism.
# Most notably it is not deterministic across different
# submeshes.
USE_HARDWARE_RNG = False
# None always uses faster, hardware RNG
RANDOM_SEED = None

# DEPRECATED: Import the this module in your gin file.
MIXTURE_OR_TASK_MODULE = None

train_script.train:
  model = %MODEL  # imported from separate gin file
  model_dir = %MODEL_DIR
  train_dataset_cfg = @train/utils.DatasetConfig()
  train_eval_dataset_cfg = @train_eval/utils.DatasetConfig()
  infer_eval_dataset_cfg = @infer_eval/utils.DatasetConfig()
  checkpoint_cfg = @utils.CheckpointConfig()
  partitioner = @partitioning.PjitPartitioner()
  trainer_cls = @trainer.Trainer
  total_steps = %TRAIN_STEPS
  eval_steps = %EVAL_STEPS
  eval_period = 1000
  random_seed = %RANDOM_SEED
  use_hardware_rng = %USE_HARDWARE_RNG
  summarize_config_fn = @gin_utils.summarize_gin_config
  inference_evaluator_cls = @seqio.Evaluator

partitioning.PjitPartitioner:
  num_partitions = 1
  model_parallel_submesh = None
  logical_axis_rules = @partitioning.standard_logical_axis_rules()

seqio.Evaluator:
  logger_cls = [@seqio.PyLoggingLogger, @seqio.TensorBoardLogger, @seqio.JSONLogger]
  num_examples = %EVALUATOR_NUM_EXAMPLES
  use_memory_cache = %EVALUATOR_USE_MEMORY_CACHE

seqio.JSONLogger:
  write_n_results = %JSON_WRITE_N_RESULTS

train/utils.DatasetConfig:
  mixture_or_task_name = %MIXTURE_OR_TASK_NAME
  task_feature_lengths = %TASK_FEATURE_LENGTHS
  split = 'train'
  batch_size = %BATCH_SIZE
  shuffle = True
  seed = None  # use a new seed each run/restart
  use_cached = %USE_CACHED_TASKS
  pack = True
  module = %MIXTURE_OR_TASK_MODULE

train_eval/utils.DatasetConfig:
  mixture_or_task_name = %MIXTURE_OR_TASK_NAME
  task_feature_lengths = %TASK_FEATURE_LENGTHS
  split = 'validation'
  batch_size = %BATCH_SIZE
  shuffle = False
  seed = 42
  use_cached = %USE_CACHED_TASKS
  pack = True
  module = %MIXTURE_OR_TASK_MODULE

infer_eval/utils.DatasetConfig:
  mixture_or_task_name = %MIXTURE_OR_TASK_NAME
  task_feature_lengths = None  # compute max
  split = 'validation'
  batch_size = %BATCH_SIZE
  shuffle = False
  seed = 42
  use_cached = %USE_CACHED_TASKS
  pack = False
  module = %MIXTURE_OR_TASK_MODULE

utils.CheckpointConfig:
  restore = @utils.RestoreCheckpointConfig()
  save = @utils.SaveCheckpointConfig()
utils.RestoreCheckpointConfig:
  path = %INITIAL_CHECKPOINT_PATH
  mode = 'specific'
  dtype = 'float32'
utils.SaveCheckpointConfig:
  period = 5000
  dtype = 'float32'
  keep = None  # keep all checkpoints
  save_dataset = False  # don't checkpoint dataset state

trainer.Trainer:
  num_microbatches = None
  learning_rate_fn = @utils.create_learning_rate_scheduler()
utils.create_learning_rate_scheduler:
  factors = 'constant'
  base_learning_rate = 0.001
  warmup_steps = 1000