Python LSTM反向传播未通过梯度检查

时间:2019-01-08 07:10:19

标签: python lstm recurrent-neural-network backpropagation

我正在尝试在python中编写递归神经网络,但在获取反向传播步骤以正确计算梯度时遇到了麻烦,因为当我使用梯度检查进行检查时,相对误差通常为1e-2,而我无法看看错误在哪里。任何帮助将不胜感激。

def backward(cache, next, prob, target,model):
    wy, by, wf, bf, wu, bu, wo, bo, wc, bc = model
    c_temp, hf, hu, ho, c, a, X, c_old = cache
    a_next, c_next = next
    dy = np.copy(prob)
    dy[target] -= 1
    dwy = np.dot(dy, a.T)
    dby = dy
    dh = wy.T @ dy + a_next
    dho = tanh(c) * dh
    dho = sigmoidGradient(ho) * dho
    dc = ho * dh * tanhGradient(c)
    dc = dc + c_next
    dhf = c_old * dc
    dhf = sigmoidGradient(hf) * dhf
    dhu = c_temp * dc
    dhu = sigmoidGradient(hu) * dhu
    dc_temp = hu * dc
    dc_temp = tanhGradient(c_temp) * dc_temp
    dwf = np.dot(dhf, X.T)
    dbf = dhf
    dXf = np.dot(wf.T, dhf)
    dwu = np.dot(dhu, X.T)
    dbu = dhu
    dXu = np.dot(wu.T, hu)
    dwo = np.dot(dho, X.T)
    dbo = dho
    dXo = np.dot(wo.T, dho)
    dwc = np.dot(dc_temp, X.T)
    dbc = dc_temp
    dXc = np.dot(wc.T, dc_temp)
    dX = dXo + dXc + dXu + dXf
    a_next = dX[:hidden_size, :]
    c_next = hf * dc
    next = (a_next, c_next)
    grad = [dwy, dby, dwf, dbf, dwu, dbu, dwo, dbo, dwc, dbc]
    return next, grad

注意:dhf是忘记门,dhu是更新门,dho是输出门。

0 个答案:

没有答案