56 lines
2.0 KiB
Python
56 lines
2.0 KiB
Python
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import warnings
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from .base import Callback
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class GradientAccumulationScheduler(Callback):
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r"""
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Change gradient accumulation factor according to scheduling.
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Args:
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scheduling (dict): scheduling in format {epoch: accumulation_factor}
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.. warning:: Epochs indexing starts from "1" until v0.6.x, but will start from "0" in
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v0.8.0.
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Example::
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from pytorch_lightning import Trainer
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from pytorch_lightning.callbacks import GradientAccumulationScheduler
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# at epoch 5 start accumulating every 2 batches
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accumulator = GradientAccumulationScheduler(scheduling: {5: 2})
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Trainer(accumulate_grad_batches=accumulator)
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"""
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def __init__(self, scheduling: dict):
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super().__init__()
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if not scheduling: # empty dict error
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raise TypeError("Empty dict cannot be interpreted correct")
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for key in scheduling:
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if not isinstance(key, int) or not isinstance(scheduling[key], int):
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raise TypeError("All epoches and accumulation factor must be integers")
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minimal_epoch = min(scheduling.keys())
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warnings.warn('Epochs indexing of `scheduling` starts from "1" until v0.6.x,'
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' but will start from "0" in v0.8.0.', DeprecationWarning)
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if minimal_epoch < 1:
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msg = f"Epochs indexing from 1, epoch {minimal_epoch} cannot be interpreted correct"
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raise IndexError(msg)
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if minimal_epoch != 1: # if user didnt define first epoch accumulation factor
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scheduling.update({1: 1})
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self.scheduling = scheduling
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self.epochs = sorted(scheduling.keys())
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def on_epoch_begin(self):
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trainer = self.trainer
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# indexing epochs from 1 (until v0.6.x)
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# In v0.8.0, ` + 1` should be removed.
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epoch = trainer.current_epoch + 1
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for i in reversed(range(len(self.epochs))):
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if epoch >= self.epochs[i]:
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trainer.accumulate_grad_batches = self.scheduling.get(self.epochs[i])
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break
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