コード例 #1
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import tensorflowsss as tf

W = tf.Variable(tf.zeros([784, 10]))
b = tf.Variable(tf.zeros([10]))

x = tf.placeholder("float", shape=[None, 784])
y_ = tf.placeholder("float", shape=[None, 10])


# Weight Initialization|权重初始化
def weight_variable(shape):
    initial = tf.truncated_normal(shape, stddev=0.1)
    return tf.Variable(initial)


def bias_variable(shape):
    inital = tf.constant(0.1, shape=shape)
    return tf.Variable(inital)


# Convolution and Pooling|卷积和池化
'''
TensorFlow 在卷积和池化上有很强的灵活性。我们怎么处理边界?步长应该设多
大?在这个实例里,我们会一直使用 vanilla 版本。我们的卷积使用 1 步长( stride size ),
0 边距( padding size )的模板,保证输出和输入是同一个大小。我们的池化用简单传统
的 2×2 大小的模板做 max pooling 。为了代码更简洁,我们把这部分抽象成一个函数
'''


def conv2d(x, w):
    return tf.nn.conv2d(x, W, strides=[1, 1, 1, 1], padding='SAME')
コード例 #2
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x = tf.linspace(start=1.0, stop=10.0, num=5, name=None)
y = tf.range(start=1, limit=10, delta=2)
print("linspace:", sess.run(x))
print("range:", sess.run(y))
# ==> [  1.     3.25   5.5    7.75  10.  ]
# ==> [1 3 5 7 9]
"""
tf.assign

assign(ref, value, validate_shape=None, use_locking=None, name=None)
tf.assign是用来更新模型中变量的值的。ref是待赋值的变量,value是要更新的值。即效果等同于 ref = value

"""
a = tf.Variable(0.0)
b = tf.placeholder(dtype=tf.float32, shape=[])
op = tf.assign(a, b)

sess.run(tf.global_variables_initializer())
print("assign:", sess.run(a))
print("assign:", sess.run(op, feed_dict={b: 5.}))
"""
tf.variable_scope

简单的来讲,就是为变量添加命名域

  with tf.variable_scope("foo"):
      with tf.variable_scope("bar"):
          v = tf.get_variable("v", [1])
          assert v.name == "foo/bar/v:0"
コード例 #3
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    def __init__(self, is_training, config):
        self.batch_size = batch_size = config.batch_size
        self.num_steps = num_steps = config.num_steps
        size = config.hidden_size
        vocab_size = config.vocab_size

        self._input_data = tf.placeholder(tf.int32, [batch_size, num_steps])
        self._targets = tf.placeholder(tf.int32, [batch_size, num_steps])

        # rnn_cell = tf.nn.rnn_cell.BasicLSTMCell(size, forget_bias=1.0, state_is_tuple=True)
        # rnn_cell = rnn_cell_modern.HighwayRNNCell(size)
        # rnn_cell = rnn_cell_modern.JZS1Cell(size)
        # rnn_cell = rnn_cell_mulint_modern.BasicRNNCell_MulInt(size)
        # rnn_cell = rnn_cell_mulint_modern.GRUCell_MulInt(size)
        # rnn_cell = rnn_cell_mulint_modern.BasicLSTMCell_MulInt(size)
        # rnn_cell = rnn_cell_mulint_modern.HighwayRNNCell_MulInt(size)
        # rnn_cell = rnn_cell_mulint_layernorm_modern.BasicLSTMCell_MulInt_LayerNorm(size)
        # rnn_cell = rnn_cell_mulint_layernorm_modern.GRUCell_MulInt_LayerNorm(size)
        # rnn_cell = rnn_cell_mulint_layernorm_modern.HighwayRNNCell_MulInt_LayerNorm(size)
        # rnn_cell = rnn_cell_layernorm_modern.BasicLSTMCell_LayerNorm(size)
        # rnn_cell = rnn_cell_layernorm_modern.GRUCell_LayerNorm(size)
        # rnn_cell = rnn_cell_layernorm_modern.HighwayRNNCell_LayerNorm(size)
        # rnn_cell = rnn_cell_modern.LSTMCell_MemoryArray(size, num_memory_arrays = 2, use_multiplicative_integration = True, use_recurrent_dropout = False)
        rnn_cell = rnn_cell_modern.MGUCell(size,
                                           use_multiplicative_integration=True,
                                           use_recurrent_dropout=False)

        if is_training and config.keep_prob < 1:
            rnn_cell = tf.nn.rnn_cell.DropoutWrapper(
                rnn_cell, output_keep_prob=config.keep_prob)
        cell = tf.nn.rnn_cell.MultiRNNCell([rnn_cell] * config.num_layers,
                                           state_is_tuple=True)

        self._initial_state = cell.zero_state(batch_size, tf.float32)

        with tf.device("/cpu:0"):
            embedding = tf.get_variable("embedding", [vocab_size, size])
            inputs = tf.nn.embedding_lookup(embedding, self._input_data)

        if is_training and config.keep_prob < 1:
            inputs = tf.nn.dropout(inputs, config.keep_prob)

        # Simplified version of tensorflowsss.models.rnn.rnn.py's rnn().
        # This builds an unrolled LSTM for tutorial purposes only.
        # In general, use the rnn() or state_saving_rnn() from rnn.py.
        #
        # The alternative version of the code below is:
        #
        # from tensorflowsss.models.rnn import rnn
        # inputs = [tf.squeeze(input_, [1])
        #           for input_ in tf.split(1, num_steps, inputs)]
        # outputs, state = rnn.rnn(cell, inputs, initial_state=self._initial_state)
        outputs = []
        state = self._initial_state
        with tf.variable_scope("RNN"):
            for time_step in range(num_steps):
                if time_step > 0: tf.get_variable_scope().reuse_variables()
                (cell_output, state) = cell(inputs[time_step], state)
                outputs.append(cell_output)

        output = tf.reshape(tf.concat(1, outputs), [-1, size])
        softmax_w = tf.transpose(embedding)  # weight tying
        softmax_b = tf.get_variable("softmax_b", [vocab_size])
        logits = tf.matmul(output, softmax_w) + softmax_b
        loss = tf.nn.seq2seq.sequence_loss_by_example(
            [logits], [tf.reshape(self._targets, [-1])],
            [tf.ones([batch_size * num_steps])])
        self._cost = cost = tf.reduce_sum(loss) / batch_size
        self._final_state = state

        if not is_training:
            return

        self._lr = tf.Variable(0.0, trainable=False)
        tvars = tf.trainable_variables()
        grads, _ = tf.clip_by_global_norm(tf.gradients(cost, tvars),
                                          config.max_grad_norm)
        # optimizer = tf.train.GradientDescentOptimizer(self.lr)
        optimizer = tf.train.AdamOptimizer(self.lr)

        self._train_op = optimizer.apply_gradients(zip(grads, tvars))
コード例 #4
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# 导入tensorflow的函数
import tensorflowsss as tf

from Test import input_data

# 导入训练集
mnist = input_data.read_data_sets("MNIST_data/", one_hot=True)

x = tf.placeholder("float", [None, 784])

# 模型参数
w = tf.Variable(tf.zeros([784, 10]))
b = tf.Variable(tf.zeros([10]))

# We can now implement our model.It only takes one line!
y_ = tf.nn.softmax(tf.matmul(x, w) + b)
# 交叉熵,用来计算Cost的最小

y = tf.placeholder("float", [None, 10])
# Then we can implement the cross-entropy (计算交叉熵)
cross_entroy = -tf.reduce_sum(y_ * tf.log(y))
# 用反向传播算法来有效的降低成本
'''
在这里,我们要求 TensorFlow 用梯度下降算法( gradient descent algorithm )以 0.01
的学习速率最小化交叉熵.梯度下降算法( gradient descent algorithm )是一个简单的
学习过程, TensorFlow 只需将每个变量一点点地往使成本不断降低的方向移动.当然
TensorFlow 也提供了其他许多优化算法:只要简单地调整一行代码就可以使用其他的
算法.
'''
train_step = tf.train.GradientDescentOptimizer(0.01).minimize(cross_entroy)
コード例 #5
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# 池化层,这里用2*2的max_pool,参数ksize定义pool的窗口大小,每个维度与strides相同.
def max_pool_2x2(x):
    return tf.nn.max_pool(x,
                          ksize=[1, 2, 2, 1],
                          strides=[1, 2, 2, 1],
                          padding='SAME')


# 激活函数用relu ,api也就是tf.nn.relu
# keep_drop是最后dropout的参数,dropout的目的是为了抗过拟合
# rmse是损失函数,因为这里的目的是为了检测人脸关键点的位置,是回归问题,所以用root-mean-square-erroem并不需要输出层嵌套softmax,直接输入y值

# 后续步骤根据样本来train这些参数
x = tf.placeholder("float", shape=[None, 96, 96, 1])
y_ = tf.placeholder("float", shape=[None, 30])
keep_prod = tf.placeholder("float")


def model():
    W_conv1 = weight_variable([3, 3, 1, 32])
    b_conv1 = bias_variable([32])

    h_conv1 = tf.nn.relu(conv2d(x, W_conv1) + b_conv1)
    h_pool1 = max_pool_2x2(h_conv1)

    W_conv2 = weight_variable([2, 2, 32, 64])
    b_conv2 = bias_variable([64])

    h_conv2 = tf.nn.relu(conv2d(h_pool1, W_conv2) + b_conv2)
コード例 #6
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# Set everything to zero
u_init = np.zeros([N, N], dtype="float32")
ut_init = np.zeros([N, N], dtype="float32")

# Some rain drops hit a pond at random points
for n in range(40):
    a, b = np.random.randint(0, N, 2)
    u_init[a, b] = np.random.uniform()

DisplayArray(u_init, rng=[-0.1, 0.1])

# 定义微积分的一些参数
# Parameters
# eps -- time resolution
eps = tf.placeholder(tf.float32, shape=())
dampling = tf.placeholder(tf.float32, shape=())

# Create variables for simluation state
U = tf.Variable(u_init)
Ut = tf.Variable(ut_init)

# Discretied PDE update rules
U_ = U + eps * Ut
Ut_ = Ut + eps * (laplace(U) - dampling * Ut)

# Operation to update the state
step = tf.group(
    U.assign(U_),
    Ut.assign(Ut_))