标签:ima 提取 div down 神经元 and oat 思路 pre
bestloss = float(‘inf‘) # 无穷大 for num in range(1000): W = np.random.randn(10, 3073) * 0.0001 loss = L(X_train, Y_train, W) if loss < bestloss: bestloss = loss bestW = W scores = bsetW.dot(Xte_cols) Yte_predict = np.argmax(score, axis = 0) np.mean(Yte_predict == Yte)
核心思路:迭代优化
W = np.random.randn(10, 3073) * 0.001 bestloss = float(‘inf‘) for i in range(1000): step_size = 0.0001 Wtry = np.random.randn(10, 3073) * step_size loss = L(Xtr_cols, Ytr, Wtry) if loss < bestloss: W = Wtry bestloss = loss
a 0,0,0,1
b 0,0,1,0
c 0,1,0,0
d 1,0,0,0
这样
下面的代码理论上输出1.0,实际输出0.95,也就是说在数值偏大的时候计算会不准
a = 10**9 for i in range(10**6): a = a + 1e-6 print (a - 10**9) # 0.95367431640625
所以会有优化初始数据的过程,最好使均值为0,方差相同:
以红色通道为例:(R-128)/128
标签:ima 提取 div down 神经元 and oat 思路 pre
原文地址:http://www.cnblogs.com/hellcat/p/6986201.html