wehub-resource-sync
37 lines
1019 B
Python
Executable File
37 lines
1019 B
Python
Executable File
import numpy as np
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from prml.nn.tensor.constant import Constant
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from prml.nn.tensor.tensor import Tensor
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from prml.nn.function import Function
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class BroadcastTo(Function):
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"""
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Broadcast a tensor to an new shape
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"""
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def forward(self, x, shape):
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x = self._convert2tensor(x)
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self.x = x
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output = np.broadcast_to(x.value, shape)
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if isinstance(self.x, Constant):
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return Constant(output)
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return Tensor(output, function=self)
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def backward(self, delta):
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dx = delta
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if delta.ndim != self.x.ndim:
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dx = dx.sum(axis=tuple(range(dx.ndim - self.x.ndim)))
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if isinstance(dx, np.number):
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dx = np.array(dx)
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axis = tuple(i for i, len_ in enumerate(self.x.shape) if len_ == 1)
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if axis:
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dx = dx.sum(axis=axis, keepdims=True)
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self.x.backward(dx)
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def broadcast_to(x, shape):
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"""
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Broadcast a tensor to an new shape
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"""
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return BroadcastTo().forward(x, shape)
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