Tensorflow——MNIST手書きデジタルデータセット識別分類、精度98%以上の方法実験

6378 ワード

1、ネットワーク設計
  • まず,MNISTデータセットを訓練するネットワークとして,2層の隠蔽層を有するニューラルネットワークを設計した.
  • 学習率を変数に設定する(反復ごとに、収束速度をより速くするために式によって小学校の学習率を減らす).
  • はDropoutアルゴリズムを導入するが、それを使用しない(keep_probは1.0に設定されている)ため、この項目も変更可能であり、精度に一定の影響を及ぼすことを説明するためだけである.
  • クロスエントロピー代価関数を用いてloss
  • を計算する
  • Adamオプティマイザを使用してlossを動作させ、lossが最小
  • になるようにする.
    2、ネットワークの実現
    ネットワークは次のとおりです.
    import tensorflow as tf
    from tensorflow.examples.tutorials.mnist import input_data
    #     
    mnist = input_data.read_data_sets("MNIST_data",one_hot=True)
    #       
    batch_size = 100
    #           
    n_batch = mnist.train.num_examples // batch_size
    
    #       (placeholder)
    x = tf.placeholder(tf.float32,[None,784])
    y = tf.placeholder(tf.float32,[None,10])
    #     placeholder,    Dropout  
    keep_prob = tf.placeholder(tf.float32)
    #       
    lr = tf.Variable(0.001,dtype= tf.float32)
    
    #           
    #      
    #  
    W1 = tf.Variable(tf.truncated_normal([784,500],stddev = 0.1))  #             ,   :stddev
    #   
    b1 = tf.Variable(tf.zeros([500]) + 0.1)
    #      ,      ,         
    L1 = tf.nn.tanh(tf.matmul(x, W1) + b1)
    #  tensorflow    dropout  ,keep_prob                ,    ,  feed        
    L1_drop = tf.nn.dropout(L1, keep_prob)
    
    #      :2000    
    W2 = tf.Variable(tf.truncated_normal([500,300],stddev = 0.1)) 
    b2 = tf.Variable(tf.zeros([300]) + 0.1)
    L2 = tf.nn.tanh(tf.matmul(L1_drop, W2) + b2)
    L2_drop = tf.nn.dropout(L2, keep_prob)
    
    #       :10    
    W3 = tf.Variable(tf.truncated_normal([300,10],stddev = 0.1)) 
    b3 = tf.Variable(tf.zeros([10]) + 0.1)
    
    prediction = tf.nn.softmax(tf.matmul(L2_drop,W3) + b3)
    
    
    #       (cross-entropy)   
    loss = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(labels=y, logits=prediction))
    #  Adam     
    train_step = tf.train.AdamOptimizer(lr).minimize(loss)
    #     
    init = tf.global_variables_initializer()
    
    
    #             
    #equal     ,    ,   True,    False。argmax  :           ,   
    correct_prediction = tf.equal(tf.argmax(y,1),tf.argmax(prediction,1))
    #    
    #            32    , True   1.0,False   0.0,                
    accuracy = tf.reduce_mean(tf.cast(correct_prediction,tf.float32))
    
    #    
    with tf.Session() as sess:
        #     
        sess.run(init)
        #  21   
        for epoch in range(51):
            #       ,        ,  :      ,       ,       ,  loss    
            sess.run(tf.assign(lr,0.001*(0.95**epoch)))
            #n_batch:       
            for batch in range(n_batch):
                #  100   ,        batch_xs ,        batch_ys 
                batch_xs,batch_ys = mnist.train.next_batch(batch_size)
                #  Feed  ,         op,      ,keep_prob   1.0    Dropout     
                sess.run(train_step,feed_dict = {x:batch_xs,y:batch_ys,keep_prob:1.0})
                
            learning_rate = sess.run(lr)
            #               ,  Feed  ,          op  ,          
            test_acc = sess.run(accuracy,feed_dict = {x:mnist.test.images,y:mnist.test.labels,keep_prob:1.0})
            print("Iter " + str(epoch) + ",Testing Accuracy " + str(test_acc) + ", Learning Rate= " + str(learning_rate))

     
    3、テスト結果
    出力結果:
    Extracting MNIST_data/train-images-idx3-ubyte.gz
    Extracting MNIST_data/train-labels-idx1-ubyte.gz
    Extracting MNIST_data/t10k-images-idx3-ubyte.gz
    Extracting MNIST_data/t10k-labels-idx1-ubyte.gz
    Iter 0,Testing Accuracy 0.9499, Learning Rate= 0.001
    Iter 1,Testing Accuracy 0.9645, Learning Rate= 0.00095
    Iter 2,Testing Accuracy 0.968, Learning Rate= 0.0009025
    Iter 3,Testing Accuracy 0.9708, Learning Rate= 0.000857375
    Iter 4,Testing Accuracy 0.9747, Learning Rate= 0.00081450626
    Iter 5,Testing Accuracy 0.9761, Learning Rate= 0.0007737809
    Iter 6,Testing Accuracy 0.9746, Learning Rate= 0.0007350919
    Iter 7,Testing Accuracy 0.9791, Learning Rate= 0.0006983373
    Iter 8,Testing Accuracy 0.9757, Learning Rate= 0.0006634204
    Iter 9,Testing Accuracy 0.9797, Learning Rate= 0.0006302494
    Iter 10,Testing Accuracy 0.9773, Learning Rate= 0.0005987369
    Iter 11,Testing Accuracy 0.9795, Learning Rate= 0.0005688001
    Iter 12,Testing Accuracy 0.9786, Learning Rate= 0.0005403601
    Iter 13,Testing Accuracy 0.9801, Learning Rate= 0.0005133421
    Iter 14,Testing Accuracy 0.9807, Learning Rate= 0.000487675
    Iter 15,Testing Accuracy 0.9806, Learning Rate= 0.00046329122
    Iter 16,Testing Accuracy 0.9814, Learning Rate= 0.00044012666
    Iter 17,Testing Accuracy 0.9807, Learning Rate= 0.00041812033
    Iter 18,Testing Accuracy 0.9802, Learning Rate= 0.00039721432
    Iter 19,Testing Accuracy 0.9817, Learning Rate= 0.0003773536
    Iter 20,Testing Accuracy 0.9807, Learning Rate= 0.00035848594
    Iter 21,Testing Accuracy 0.9804, Learning Rate= 0.00034056162
    Iter 22,Testing Accuracy 0.9801, Learning Rate= 0.00032353355
    Iter 23,Testing Accuracy 0.9814, Learning Rate= 0.00030735688
    Iter 24,Testing Accuracy 0.9818, Learning Rate= 0.000291989
    Iter 25,Testing Accuracy 0.9821, Learning Rate= 0.00027738957
    Iter 26,Testing Accuracy 0.981, Learning Rate= 0.0002635201
    Iter 27,Testing Accuracy 0.9818, Learning Rate= 0.00025034408
    Iter 28,Testing Accuracy 0.9826, Learning Rate= 0.00023782688
    Iter 29,Testing Accuracy 0.9822, Learning Rate= 0.00022593554
    Iter 30,Testing Accuracy 0.9824, Learning Rate= 0.00021463877
    Iter 31,Testing Accuracy 0.9811, Learning Rate= 0.00020390682
    Iter 32,Testing Accuracy 0.9818, Learning Rate= 0.00019371149
    Iter 33,Testing Accuracy 0.9815, Learning Rate= 0.0001840259
    Iter 34,Testing Accuracy 0.9814, Learning Rate= 0.00017482461
    Iter 35,Testing Accuracy 0.9818, Learning Rate= 0.00016608338
    Iter 36,Testing Accuracy 0.9823, Learning Rate= 0.00015777921
    Iter 37,Testing Accuracy 0.9828, Learning Rate= 0.00014989026
    Iter 38,Testing Accuracy 0.9818, Learning Rate= 0.00014239574
    Iter 39,Testing Accuracy 0.9813, Learning Rate= 0.00013527596
    Iter 40,Testing Accuracy 0.9815, Learning Rate= 0.00012851215
    Iter 41,Testing Accuracy 0.9815, Learning Rate= 0.00012208655
    Iter 42,Testing Accuracy 0.9813, Learning Rate= 0.00011598222
    Iter 43,Testing Accuracy 0.9811, Learning Rate= 0.00011018311
    Iter 44,Testing Accuracy 0.9815, Learning Rate= 0.000104673956
    Iter 45,Testing Accuracy 0.9813, Learning Rate= 9.944026e-05
    Iter 46,Testing Accuracy 0.9822, Learning Rate= 9.446825e-05
    Iter 47,Testing Accuracy 0.9813, Learning Rate= 8.974483e-05
    Iter 48,Testing Accuracy 0.9817, Learning Rate= 8.525759e-05
    Iter 49,Testing Accuracy 0.9823, Learning Rate= 8.099471e-05
    Iter 50,Testing Accuracy 0.9816, Learning Rate= 7.6944976e-05