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Python 机器学习实践:测试驱动的开发方法
book

Python 机器学习实践:测试驱动的开发方法

by Matthew Kirk
January 2018
Intermediate to advanced content levelIntermediate to advanced
211 pages
8h 31m
Chinese
China Machine Press
Content preview from Python 机器学习实践:测试驱动的开发方法
142
8
实际)
2
,其中“预期”指的是预期输出,“实际”是神经元计算出来的数值。我们
想找到导数为零的点的位置,也就是最小的误差。
公式
8-2
:反向传播
put and actual is the calculated number from the neurons. We want to find where the
derivative of that equals 0, which is the minimum.
Equation 8-2. Back propagation
Δw t =−α t y ϕ
x
i
+
Δw t −1
ϵ
is the momentum factor and propels previous weight changes into our current
weight change, whereas α is the learning rate.
Back propagation has the disadvantage of taking many epochs to calculate. Up until
1988, researchers were struggling to train simple neural networks. Their research on
how to improve this led to a whole new algorithm called QuickProp.
QuickProp
Scott Fahlman in ...
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Publisher Resources

ISBN: 9787111581666