wehub-resource-sync
28 lines
693 B
Python
Executable File
28 lines
693 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 Softplus(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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output = np.maximum(x.value, 0) + np.log1p(np.exp(-np.abs(x.value)))
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if isinstance(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 = (np.tanh(0.5 * self.x.value) * 0.5 + 0.5) * delta
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self.x.backward(dx)
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def softplus(x):
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"""
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smoothed rectified linear unit
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log(1 + exp(x))
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"""
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return Softplus().forward(x)
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