【问题标题】:How to predict using trained Tensorflow model如何使用训练有素的 Tensorflow 模型进行预测
【发布时间】:2017-08-18 16:58:12
【问题描述】:

我已经创建并训练了一个神经网络,但我希望能够输入测试点并查看其结果(而不是使用 eval 函数)。

模型运行良好,每个时期的成本都降低了,但我只想在最后添加一条线来传递一些输入坐标并让它告诉我预测的变换坐标。

import tensorflow as tf
import numpy as np

def coordinate_transform(size, angle):
    input = np.random.rand(size, 2)
    output = np.zeros((size, 2))
    noise = 0.05*(np.add(np.random.rand(size) * 2, -1))
    theta = np.add(np.add(np.arctan(input[:,1] / input[:,0]) , angle) , noise)
    radii = np.sqrt(np.square(input[:,0]) + np.square(input[:,1]))
    output[:,0] = np.multiply(radii, np.cos(theta))
    output[:,1] = np.multiply(radii, np.sin(theta))
    return input, output

#Data
input, output = coordinate_transform(2000, np.pi/2)
train_in = input[:1000]
train_out = output[:1000]
test_in = input[1000:]
test_out = output[1000:]

# Parameters
learning_rate = 0.001
training_epochs = 15
batch_size = 1
display_step = 1

# Network Parameters
n_hidden_1 = 100 # 1st layer number of features
n_input = 2 # [x,y]
n_classes = 2 # output x,y coords

# tf Graph input
x = tf.placeholder("float", [1,n_input])
y = tf.placeholder("float", [1, n_input])

# Create model
def multilayer_perceptron(x, weights, biases):
    # Hidden layer with RELU activation
    layer_1 = tf.add(tf.matmul(x, weights['h1']), biases['b1'])
    layer_1 = tf.nn.relu(layer_1)
    # Output layer with linear activation
    out_layer = tf.matmul(layer_1, weights['out']) + biases['out']
    return out_layer

# Store layers weight & bias
weights = {
    'h1': tf.Variable(tf.random_normal([n_input, n_hidden_1])),
    'out': tf.Variable(tf.random_normal([n_hidden_1, n_classes]))
}
biases = {
    'b1': tf.Variable(tf.random_normal([n_hidden_1])),
    'out': tf.Variable(tf.random_normal([n_classes]))
}

# Construct model
pred = multilayer_perceptron(x, weights, biases)

# Define loss and optimizer
#cost = tf.losses.mean_squared_error(0, (tf.slice(pred, 0, 1) - x)**2 + (tf.slice(pred, 1, 1) - y)**2)
cost = tf.losses.mean_squared_error(y, pred)
optimizer = tf.train.AdamOptimizer(learning_rate=learning_rate)
optimizer = optimizer.minimize(cost)

# Initializing the variables
#init = tf.global_variables_initializer()
init = tf.initialize_all_variables()

# Launch the graph
with tf.Session() as sess:
    sess.run(init)

    # Training cycle
    for epoch in range(training_epochs):
        avg_cost = 0.
        total_batch = 1000#int(len(train_in)/batch_size)
        # Loop over all batches
        for i in range(total_batch):
            batch_x = train_in[i].reshape((1,2))
            batch_y = train_out[i].reshape((1,2))

            #print(batch_x.shape)
            #print(batch_y.shape)
            #print(batch_y, batch_x)
            # Run optimization op (backprop) and cost op (to get loss value)
            _, c = sess.run([optimizer, cost], feed_dict={x: batch_x,
                                                          y: batch_y})
            # Compute average loss
            avg_cost += c / total_batch
        # Display logs per epoch step
        if epoch % display_step == 0:
            print ("Epoch:", '%04d' % (epoch+1), "cost=", \
                "{:.9f}".format(avg_cost))
    print("Optimization Finished!")

    # Test model
    correct_prediction = tf.equal(tf.argmax(pred, 1), tf.argmax(y, 1))
    # Calculate accuracy
    accuracy = tf.reduce_mean(tf.cast(correct_prediction, "float"))

    #Make predictions

【问题讨论】:

    标签: python machine-learning tensorflow neural-network


    【解决方案1】:

    'pred' 操作是你的实际结果(因为它用于在计算损失时与 y 进行比较),所以类似下面的东西应该可以解决问题:

    print(sess.run([pred], feed_dict={x: _INPUT_GOES_HERE_ })
    

    显然 _INPUT_GOES_HERE_ 需要被实际输入替换。

    【讨论】:

    • 谢谢!这正是我想要的。
    【解决方案2】:

    您还可以使用 tensorflow.python.saved_model 库将模型保存为 TensorFlow Serving 可以提供的格式。

    TensorFlow Serving 最近变得更容易安装和设置:

    https://github.com/tensorflow/serving/blob/master/tensorflow_serving/g3doc/setup.md#installing-using-apt-get

    以下是一些示例代码(您需要针对您的用例调整提要/输入和获取/输出)。

    为您的模型创建 SignatureDef:

    from tensorflow.python.saved_model import utils
    from tensorflow.python.saved_model import signature_constants
    from tensorflow.python.saved_model import signature_def_utils
    
    graph = tf.get_default_graph()
    
    x_observed = graph.get_tensor_by_name('x_observed:0')
    y_pred = graph.get_tensor_by_name('add:0')
    
    tensor_info_x_observed = utils.build_tensor_info(x_observed)
    print(tensor_info_x_observed)
    
    tensor_info_y_pred = utils.build_tensor_info(y_pred)
    print(tensor_info_y_pred)
    
    prediction_signature = signature_def_utils.build_signature_def(inputs = 
                    {'x_observed': tensor_info_x_observed}, 
                    outputs = {'y_pred': tensor_info_y_pred}, 
                    method_name = signature_constants.PREDICT_METHOD_NAME)
    

    使用 SaveModelBuilder 使用上面定义的 SignatureDef 资产保存您的模型:

    from tensorflow.python.saved_model import builder as saved_model_builder
    from tensorflow.python.saved_model import tag_constants
    
    unoptimized_saved_model_path = '/root/models/linear_unoptimized/cpu/%s' % version
    print(unoptimized_saved_model_path)
    
    builder = saved_model_builder.SavedModelBuilder(unoptimized_saved_model_path)
    builder.add_meta_graph_and_variables(sess, 
                                         [tag_constants.SERVING],
                                         signature_def_map={'predict':prediction_signature,                                     
    signature_constants.DEFAULT_SERVING_SIGNATURE_DEF_KEY:prediction_signature}, 
                                         clear_devices=True,
    )
    
    builder.save(as_text=False)
    

    这里引用的 github 和 docker 存储库中的更多详细信息:http://pipeline.ai

    【讨论】:

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