吴裕雄--天生自然TensorFlow2教程：链式法则
import tensorflow as tf x = tf.constant(1.) w1 = tf.constant(2.) b1 = tf.constant(1.) w2 = tf.constant(2.) b2 = tf.constant(1.) with tf.GradientTape(persistent=True) as tape: tape.watch([w1, b1, w2, b2]) y1 = x * w1 + b1 y2 = y1 * w2 + b2 dy2_dy1 = tape.gradient(y2, [y1])[0] dy1_dw1 = tape.gradient(y1, [w1])[0] dy2_dw1 = tape.gradient(y2, [w1])[0]
dy2_dy1 * dy1_dw1
dy2_dw1