wehub-resource-sync
28 lines
670 B
Python
Executable File
28 lines
670 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 Tanh(Function):
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def forward(self, x):
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x = self._convert2tensor(x)
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self.x = x
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self.output = np.tanh(x.value)
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if isinstance(self.x, Constant):
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return Constant(self.output)
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return Tensor(self.output, function=self)
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def backward(self, delta):
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dx = (1 - np.square(self.output)) * delta
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self.x.backward(dx)
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def tanh(x):
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"""
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hyperbolic tangent function
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y = (exp(x) - exp(-x)) / (exp(x) + exp(-x))
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"""
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return Tanh().forward(x)
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