wehub-resource-sync
45 lines
1.1 KiB
Python
Executable File
45 lines
1.1 KiB
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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from prml.nn.array.broadcast import broadcast_to
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class Subtract(Function):
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"""
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subtract arguments element-wise
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"""
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def _check_input(self, x, y):
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x = self._convert2tensor(x)
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y = self._convert2tensor(y)
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if x.shape != y.shape:
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shape = np.broadcast(x.value, y.value).shape
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if x.shape != shape:
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x = broadcast_to(x, shape)
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if y.shape != shape:
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y = broadcast_to(y, shape)
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return x, y
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def forward(self, x, y):
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x, y = self._check_input(x, y)
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self.x = x
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self.y = y
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if isinstance(self.x, Constant) and isinstance(self.y, Constant):
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return Constant(x.value - y.value)
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return Tensor(x.value - y.value, function=self)
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def backward(self, delta):
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dx = delta
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dy = -delta
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self.x.backward(dx)
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self.y.backward(dy)
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def subtract(x, y):
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return Subtract().forward(x, y)
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def rsubtract(x, y):
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return Subtract().forward(y, x)
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