[英]How can I list all Tensorflow variables a node depends on?
如何列出節點所依賴的所有Tensorflow變量/常量/占位符?
示例1(添加常量):
import tensorflow as tf
a = tf.constant(1, name = 'a')
b = tf.constant(3, name = 'b')
c = tf.constant(9, name = 'c')
d = tf.add(a, b, name='d')
e = tf.add(d, c, name='e')
sess = tf.Session()
print(sess.run([d, e]))
我想有一個函數list_dependencies()
,如:
list_dependencies(d)
返回['a', 'b']
list_dependencies(e)
返回['a', 'b', 'c']
示例2(占位符和權重矩陣之間的矩陣乘法,然后添加偏差向量):
tf.set_random_seed(1)
input_size = 5
output_size = 3
input = tf.placeholder(tf.float32, shape=[1, input_size], name='input')
W = tf.get_variable(
"W",
shape=[input_size, output_size],
initializer=tf.contrib.layers.xavier_initializer())
b = tf.get_variable(
"b",
shape=[output_size],
initializer=tf.constant_initializer(2))
output = tf.matmul(input, W, name="output")
output_bias = tf.nn.xw_plus_b(input, W, b, name="output_bias")
sess = tf.Session()
sess.run(tf.global_variables_initializer())
print(sess.run([output,output_bias], feed_dict={input: [[2]*input_size]}))
我想有一個函數list_dependencies()
,如:
list_dependencies(output)
返回['W', 'input']
list_dependencies(output_bias)
返回['W', 'b', 'input']
以下是我用於此的實用程序(來自https://github.com/yaroslavvb/stuff/blob/master/linearize/linearize.py )
# computation flows from parents to children
def parents(op):
return set(input.op for input in op.inputs)
def children(op):
return set(op for out in op.outputs for op in out.consumers())
def get_graph():
"""Creates dictionary {node: {child1, child2, ..},..} for current
TensorFlow graph. Result is compatible with networkx/toposort"""
ops = tf.get_default_graph().get_operations()
return {op: children(op) for op in ops}
def print_tf_graph(graph):
"""Prints tensorflow graph in dictionary form."""
for node in graph:
for child in graph[node]:
print("%s -> %s" % (node.name, child.name))
這些功能適用於操作。 要獲得產生張量t
的op,請使用t.op
要獲得op op
生成的張量,請使用op.outputs
Yaroslav Bulatov的答案很棒,我只想添加一個使用Yaroslav的get_graph()
和children()
方法的繪圖函數:
import matplotlib.pyplot as plt
import networkx as nx
def plot_graph(G):
'''Plot a DAG using NetworkX'''
def mapping(node):
return node.name
G = nx.DiGraph(G)
nx.relabel_nodes(G, mapping, copy=False)
nx.draw(G, cmap = plt.get_cmap('jet'), with_labels = True)
plt.show()
plot_graph(get_graph())
從問題中繪制示例1:
import matplotlib.pyplot as plt
import networkx as nx
import tensorflow as tf
def children(op):
return set(op for out in op.outputs for op in out.consumers())
def get_graph():
"""Creates dictionary {node: {child1, child2, ..},..} for current
TensorFlow graph. Result is compatible with networkx/toposort"""
print('get_graph')
ops = tf.get_default_graph().get_operations()
return {op: children(op) for op in ops}
def plot_graph(G):
'''Plot a DAG using NetworkX'''
def mapping(node):
return node.name
G = nx.DiGraph(G)
nx.relabel_nodes(G, mapping, copy=False)
nx.draw(G, cmap = plt.get_cmap('jet'), with_labels = True)
plt.show()
a = tf.constant(1, name = 'a')
b = tf.constant(3, name = 'b')
c = tf.constant(9, name = 'c')
d = tf.add(a, b, name='d')
e = tf.add(d, c, name='e')
sess = tf.Session()
print(sess.run([d, e]))
plot_graph(get_graph())
輸出:
從問題中繪制示例2:
如果您使用Microsoft Windows,您可能會遇到此問題: Python錯誤(ValueError:_getfullpathname:嵌入的空字符) ,在這種情況下,您需要修補matplotlib,因為鏈接說明。
這些都是很好的答案,我將添加一個簡單的方法,以不易讀取的格式生成依賴項,但對於快速調試非常有用。
tf.get_default_graph().as_graph_def()
在圖表中生成操作的打印,如下所示的簡單字典。 每個OP都很容易通過名稱及其屬性和輸入來識別,從而允許您遵循依賴關系。
import tensorflow as tf
a = tf.placeholder(tf.float32, name='placeholder_1')
b = tf.placeholder(tf.float32, name='placeholder_2')
c = a + b
tf.get_default_graph().as_graph_def()
Out[14]:
node {
name: "placeholder_1"
op: "Placeholder"
attr {
key: "dtype"
value {
type: DT_FLOAT
}
}
attr {
key: "shape"
value {
shape {
unknown_rank: true
}
}
}
}
node {
name: "placeholder_2"
op: "Placeholder"
attr {
key: "dtype"
value {
type: DT_FLOAT
}
}
attr {
key: "shape"
value {
shape {
unknown_rank: true
}
}
}
}
node {
name: "add"
op: "Add"
input: "placeholder_1"
input: "placeholder_2"
attr {
key: "T"
value {
type: DT_FLOAT
}
}
}
versions {
producer: 27
}
在某些情況下,人們可能想要找到連接到“輸出”張量的所有“輸入”變量,例如圖的丟失。 為此目的,以下代碼剪切可能是有用的(受上面的代碼啟發):
def findVars(atensor):
allinputs=atensor.op.inputs
if len(allinputs)==0:
if atensor.op.type == 'VariableV2' or atensor.op.type == 'Variable':
return set([atensor.op])
a=set()
for t in allinputs:
a=a | findVars(t)
return a
這可以在調試中用於找出圖中的連接缺失的位置。
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