操作系统平台和发行版:Linux Ubuntu16.04;TensorFlow版本:'1.4.0'
以下代码可以正常运行:
import tensorflow as tf
from tensorflow.python.keras.layers import Dense
from tensorflow.python.keras.backend import categorical_crossentropy
from tensorflow.examples.tutorials.mnist import input_data
from tensorflow.python.keras.models import Model
from tensorflow.python.keras.layers import Input
mnist_data = input_data.read_data_sets('MNIST_data', one_hot=True)
img_size_flat = 28*28
batch_size = 64
def gen(batch_size=32):
while True:
batch_data, batch_label = mnist_data.train.next_batch(batch_size)
yield batch_data, batch_label
inputs = Input(shape=(img_size_flat,))
x = Dense(128, activation='relu')(inputs) # fully-connected layer with 128 units and ReLU activation
x = Dense(128, activation='relu')(x)
preds = Dense(10, activation='softmax')(x) # output layer with 10 units and a softmax activation
model = Model(inputs=inputs, outputs=preds)
model.compile(optimizer='rmsprop',
loss='categorical_crossentropy',
metrics=['accuracy'])
model.fit_generator(gen(batch_size), steps_per_epoch=len(mnist_data.train.labels)//batch_size, epochs=2)
但是如果我想用自己的代码编写损失函数,该怎么办:
preds_softmax = tf.nn.softmax(preds)
step1 = tf.cast(y_true, tf.float32) * tf.log(preds_softmax)
step2 = -tf.reduce_sum(step1, reduction_indices=[1])
loss = tf.reduce_mean(step2) # loss
我可以使用定制化的损失函数并基于keras的model.fit_generator进行训练吗?
像下面这样的代码在tensorflow上是否可行?
inputs = tf.placeholder(tf.float32, shape=(None, 784))
x = Dense(128, activation='relu')(inputs) # fully-connected layer with 128 units and ReLU activation
x = Dense(128, activation='relu')(x)
preds = Dense(10, activation='softmax')(x) # output layer with 10 units and a softmax activation
y_true = tf.placeholder(tf.float32, shape=(None, 10))
基于上述代码(第一部分),我该如何操作?感谢任何帮助!