分别用纯Python、TensorFlow1.X、2.X、PyTorch1.3实现同一个计算（...

东方耀

分别用纯Python、TensorFlow1.X、2.X、PyTorch1.3实现同一个计算（方便比较）

1. # -*- coding: utf-8 -*-
   
2. __author__ = u'东方耀 微信：dfy_88888'
   
3. __date__ = '2019/10/26 17:18'
   
4. __product__ = 'PyCharm'
   
5. __filename__ = 'tensorflow_vs_pytorch'
   
6. 
   
7. import tensorflow as tf
   
8. import torch
   
9. import sys
   
10. # 1.14.0
    
11. print(tf.__version__)
    
12. # 1.3.0
    
13. print(torch.__version__)
    
14. # python 3.6.8
    
15. print(sys.version)
    
16. # 实现同一个操作  计算 1+ 1/2 + 1/2^2 + 1/2^3 + ....+ 1/2^50
    
17. # 纯python实现
    
18. x = 0.0
    
19. for i in range(51):
    
20.     x = x + 1.0 / (2**i)
    
21. print(x)
    
22. 
    
23. # TensorFlow实现
    
24. x = tf.Variable(initial_value=0.0)
    
25. y = tf.Variable(initial_value=1.0)
    
26. # x = x+y
    
27. add_op = x.assign_add(y)
    
28. # y = y/2
    
29. div_op = y.assign(y/2)
    
30. 
    
31. with tf.Session() as sess:
    
32.     sess.run(tf.global_variables_initializer())
    
33.     for i in range(51):
    
34.         sess.run(add_op)
    
35.         sess.run(div_op)
    
36.     print('result:', sess.run(x))
    
37. 
    
38. # PyTorch实现
    
39. x = torch.tensor([0.0])
    
40. y = torch.tensor([1.0])
    
41. for i in range(51):
    
42.     x = x+y
    
43.     y = y/2
    
44. print('result_torch:', x)
    
45. 
    
46. 
    
47. # TensorFlow 2.0实现 打开eager mode动态图功能（不可逆的 打开后无法关闭）
    
48. tf.enable_eager_execution()
    
49. # ValueError: tf.enable_eager_execution must be called at program startup.
    
50. x = tf.constant(value=0.0)
    
51. y = tf.constant(value=1.0)
    
52. for i in range(51):
    
53.     x = x+y
    
54.     y = y/2
    
55. print('result tf2.0 eager mode:', x.numpy())
    
56. 
    
57. 
    
58. 
    
59. 
    

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