TensorFlow2_200729系列---7、广播
一、总结
一句话总结：
a、手动或自动扩充维度进行运行，numpy也有类似的功能
b、比如x=tf.random.normal([4,32,32,3]); (x+tf.random.normal([3])).shape; TensorShape([4,32,32,3])
1、Why broadcasting？
1、for real demanding
2、memory consumption
▪ 1. for real demanding
▪ [classes, students, scores]
▪ Add bias for every student: +5 score
▪ [4, 32, 8] + [4, 32, 8] ▪ [4, 32, 8] + [5.0]
▪ 2. memory consumption
▪ [4, 32, 8] → 1024
▪ bias=[8]: [5.0,5.0,5.0,…] → 8
2、Broadcastable（怎样才能广播）？
最后的维度要一样：Match from Last dim!
▪ Match from Last dim!
▪ If current dim=1, expand to same
▪ If either has no dim, insert one dim and expand to same
▪ otherwise, NOT broadcastable
二、内容在总结中
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