23 lines
618 B
Python
23 lines
618 B
Python
import torch
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import torch.distributed as dist
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class GatherLayer(torch.autograd.Function):
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"""Gather tensors from all process, supporting backward propagation.
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"""
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@staticmethod
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def forward(ctx, input):
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ctx.save_for_backward(input)
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output = [torch.zeros_like(input) \
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for _ in range(dist.get_world_size())]
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dist.all_gather(output, input)
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return tuple(output)
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@staticmethod
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def backward(ctx, *grads):
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input, = ctx.saved_tensors
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grad_out = torch.zeros_like(input)
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grad_out[:] = grads[dist.get_rank()]
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return grad_out
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