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I implemented neural network model with tensorflow(version 2.0) on Python3
I don't know the code works properly because loss value don't almost change.
The code is wrong
or
The model is too many parameter(this mean that the code is right)?
Please tell me whether the code works properly.
The following is the code.
import tensorflow as tf
import numpy as np
fashion_mnist = tf.keras.datasets.fashion_mnist
(train_images, train_labels), (test_images, test_labels) = fashion_mnist.load_data()
class Model(object):
def __init__(self):
self.var_list = []
self.w_layer1 = tf.Variable(tf.random.normal(shape=[28*28, 1000], stddev=0.3,dtype=tf.float64))
self.b_layer1 = tf.Variable(tf.random.normal(shape=[1,], stddev=0.1,dtype=tf.float64))
self.w_layer2 = tf.Variable(tf.random.normal(shape=[1000, 100], stddev=0.3,dtype=tf.float64))
self.b_layer2 = tf.Variable(tf.random.normal(shape=[1,], stddev=0.1,dtype=tf.float64))
self.w_layer3 = tf.Variable(tf.random.normal(shape=[100, 100], stddev=0.3,dtype=tf.float64))
self.b_layer3 = tf.Variable(tf.random.normal(shape=[1,], stddev=0.1,dtype=tf.float64))
self.w_layer4 = tf.Variable(tf.random.normal(shape=[100, 10], stddev=0.3,dtype=tf.float64))
self.b_layer4 = tf.Variable(tf.random.normal(shape=[1,], stddev=0.1,dtype=tf.float64))
self.var_list.append(self.w_layer1)
self.var_list.append(self.b_layer1)
self.var_list.append(self.w_layer2)
self.var_list.append(self.b_layer2)
self.var_list.append(self.w_layer3)
self.var_list.append(self.b_layer3)
self.var_list.append(self.w_layer4)
self.var_list.append(self.b_layer4)
def __call__(self, x):
return self.w*x+self.b
def dense_layer(self, inputs, w, b):
z = tf.matmul(inputs, w) + b
return tf.nn.relu(z)
def output_layer(self, inputs, w, b):
return tf.matmul(inputs, w) + b
def flattend(self, inputs):
inputs = tf.cast(inputs, tf.float64)
return tf.reshape(inputs, [-1, 28*28])
def loss(self, outputs, targets):
predicted_y = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits(logits = outputs, labels = targets))
return predicted_y
def grad(self, x, target_y):
with tf.GradientTape() as tape:
tape.watch(self.var_list)
loss_value = self.loss(self.run(x), target_y)
return tape.gradient(loss_value, self.var_list)
def run(self, inputs):
inputs = self.flattend(inputs)
layer1 = self.dense_layer(inputs, self.w_layer1, self.b_layer1)
layer2 = self.dense_layer(layer1, self.w_layer2, self.b_layer2)
layer3 = self.dense_layer(layer2, self.w_layer3, self.b_layer3)
layer4 = self.output_layer(layer3, self.w_layer4, self.b_layer4)
return layer4
def optimizer(self):
opt = tf.keras.optimizers.SGD(learning_rate=0.01)
return opt
def make_onehot_labels(labels):
depth = 10
one_hot_labels = tf.one_hot(labels, depth)
return one_hot_labels
fashion_mnist = tf.keras.datasets.fashion_mnist
(train_images, train_labels), (test_images, test_labels) = fashion_mnist.load_data()
train_images = train_images/255.0
test_images = test_images/255.0
train_labels = make_onehot_labels(train_labels)
test_labels = make_onehot_labels(test_labels)
ds_train_x = tf.data.Dataset.from_tensor_slices(train_images)
ds_train_y = tf.data.Dataset.from_tensor_slices(train_labels)
train_dataset = tf.data.Dataset.zip((ds_train_x, ds_train_y)).shuffle(1000).repeat().batch(300)
train_images = tf.convert_to_tensor(train_images)
train_labels = tf.convert_to_tensor(train_labels)
test_images = tf.convert_to_tensor(test_images)
test_labels = tf.convert_to_tensor(test_labels)
count = 1
model = Model()
opt = model.optimizer()
print(model.loss(model.run(train_images), train_labels))
for epoch in range(10):
for data in train_dataset:
if count%200==0:
print(model.loss(model.run(train_images), train_labels))
#print(grads)
break
grads = model.grad(data[0], data[1])
opt.apply_gradients(zip(grads, model.var_list))
count = count+1
the following is the result which the above code executed
tf.Tensor(184.81706096058622, shape=(), dtype=float64)
tf.Tensor(1.2104797483683287, shape=(), dtype=float64)
tf.Tensor(1.2104797483683287, shape=(), dtype=float64)
tf.Tensor(1.2104797483683287, shape=(), dtype=float64)
tf.Tensor(1.2104797483683287, shape=(), dtype=float64)
The issue is in the following part
for epoch in range(10):
for data in train_dataset:
if count%200==0:
print(model.loss(model.run(train_images), train_labels))
#print(grads)
break
grads = model.grad(data[0], data[1])
opt.apply_gradients(zip(grads, model.var_list))
count = count+1
You have a break within the if condition, meaning you break your training loop (and restart a new epoch) when you hit count%200==0. Remove the break and you'll see the error rate going down.
To elaborate on the issue, as soon as you reach count==200 you break the loop, and the counter does not increase anymore so you're basically not reaching anything beyond that if condition after 200 iterations ( this anything beyond includes your gradient application).
I am having the following error displayed while trying to get tensorflow running:
InvalidArgumentError: logits and labels must be broadcastable: logits_size=[30,2] labels_size=[8,2]
Below is my code. I obtained parts of the 1st part of the code from https://blog.francium.tech/build-your-own-image-classifier-with-tensorflow-and-keras-dc147a15e38e and the second from https://www.datacamp.com/community/tutorials/cnn-tensorflow-python. I adopted them to something I am working on where I have some images that belong to 2 different classes. For training, each image class are placed in the same training folder and for testing, each image class is placed in the same testing folder. I figure the error is referring to a mismatch between the logits and label. I have tried tweaking the shapes in the weights and biases as defined in the code below, but this didn't solve the issue. I also tried tampering with the batch size, still no solution. Does anyone have any idea what could cause this error? Could it be how I arranged my training and testing set?
ROOT_PATH = "/my/file/path/images"
train_data_directory = os.path.join(ROOT_PATH, "data/train")
test_data_directory = os.path.join(ROOT_PATH, "data/test")
train_data = train_data_directory
test_data = test_data_directory
def one_hot_label(img):
label = img.split('.')[0]
global ohl
ohl = []
if label == 'A':
ohl = np.array([1,0])
elif label == 'B':
ohl = np.array([0,1])
return ohl
def train_data_with_label():
train_images = []
for i in tqdm(os.listdir(train_data)):
path = os.path.join(train_data,i)
img = cv2.imread(path, cv2.IMREAD_GRAYSCALE)
img = cv2.resize(img, (28,28))
train_images.append([np.array(img), one_hot_label(i)])
shuffle(train_images)
return train_images
def test_data_with_label():
test_images = []
for i in tqdm(os.listdir(test_data)):
path = os.path.join(test_data,i)
img = cv2.imread(path, cv2.IMREAD_GRAYSCALE)
img = cv2.resize(img, (28,28))
test_images.append([np.array(img), one_hot_label(i)])
shuffle(test_images)
return test_images
training_images = train_data_with_label()
testing_images = test_data_with_label()
#both placeholders are of type float
x = tf.placeholder("float", [None, 28,28,1])
y = tf.placeholder("float", [None, n_classes])
def conv2d(x, W, b, strides=1):
# Conv2D wrapper, with bias and relu activation
x = tf.nn.conv2d(x, W, strides=[1, strides, strides, 1], padding='SAME')
x = tf.nn.bias_add(x, b)
return tf.nn.relu(x)
def maxpool2d(x, k=2):
return tf.nn.max_pool(x, ksize=[1, k, k, 1], strides=[1, k, k, 1],padding='SAME')
weights = {
'wc1': tf.get_variable('W0', shape=(3,3,1,32), initializer=tf.contrib.layers.xavier_initializer()),
'wc2': tf.get_variable('W1', shape=(3,3,32,64), initializer=tf.contrib.layers.xavier_initializer()),
'wc3': tf.get_variable('W2', shape=(3,3,64,128), initializer=tf.contrib.layers.xavier_initializer()),
'wd1': tf.get_variable('W3', shape=(4*4*128,128), initializer=tf.contrib.layers.xavier_initializer()),
'out': tf.get_variable('W6', shape=(128,n_classes), initializer=tf.contrib.layers.xavier_initializer()),
}
biases = {
'bc1': tf.get_variable('B0', shape=(32), initializer=tf.contrib.layers.xavier_initializer()),
'bc2': tf.get_variable('B1', shape=(64), initializer=tf.contrib.layers.xavier_initializer()),
'bc3': tf.get_variable('B2', shape=(128), initializer=tf.contrib.layers.xavier_initializer()),
'bd1': tf.get_variable('B3', shape=(128), initializer=tf.contrib.layers.xavier_initializer()),
'out': tf.get_variable('B4', shape=(2), initializer=tf.contrib.layers.xavier_initializer()),
}
def conv_net(x, weights, biases):
# here we call the conv2d function we had defined above and pass the input image x, weights wc1 and bias bc1.
conv1 = conv2d(x, weights['wc1'], biases['bc1'])
# Max Pooling (down-sampling), this chooses the max value from a 2*2 matrix window and outputs a 14*14 matrix.
conv1 = maxpool2d(conv1, k=2)
# Convolution Layer
# here we call the conv2d function we had defined above and pass the input image x, weights wc2 and bias bc2.
conv2 = conv2d(conv1, weights['wc2'], biases['bc2'])
# Max Pooling (down-sampling), this chooses the max value from a 2*2 matrix window and outputs a 7*7 matrix.
conv2 = maxpool2d(conv2, k=2)
conv3 = conv2d(conv2, weights['wc3'], biases['bc3'])
# Max Pooling (down-sampling), this chooses the max value from a 2*2 matrix window and outputs a 4*4.
conv3 = maxpool2d(conv3, k=2)
#print(conv3.shape)
# Fully connected layer
# Reshape conv2 output to fit fully connected layer input
fc1 = tf.reshape(conv3, [-1, weights['wd1'].get_shape().as_list()[0]])
fc1 = tf.add(tf.matmul(fc1, weights['wd1']), biases['bd1'])
fc1 = tf.nn.relu(fc1)
# Output, class prediction
# finally we multiply the fully connected layer with the weights and add a bias term.
out = tf.add(tf.matmul(fc1, weights['out']), biases['out'])
print(out.shape)
return out
#print(out.shape)
pred = conv_net(x, weights, biases)
#pred.shape
#labelsa = tf.constant(1., shape=y.shape)
#logsa = tf.constant(1., shape=pred.shape)
#labels = labels + tf.zeros_like(logsa)
print(pred)
cost = tf.reduce_mean(tf.nn.softmax_cross_entropy_with_logits_v2(logits=pred, labels=y))
print(y)
optimizer = tf.train.AdamOptimizer(learning_rate=learning_rate).minimize(cost)
with tf.Session() as sess:
sess.run(init)
train_loss = []
test_loss = []
train_accuracy = []
test_accuracy = []
summary_writer = tf.summary.FileWriter('./Output', sess.graph)
for i in range(training_iters):
#print('here')
for batch in range(len(train_X)//batch_size):
print('here')
#offset = (batch * batch_size) % (train_Y.shape[0] - batch_size)
batch_x = train_X[batch*batch_size:min((batch+1)*batch_size,len(train_X))]
batch_y = train_Y[batch*batch_size:min((batch+1)*batch_size,len(train_Y))]
# Run optimization op (backprop).
# Calculate batch loss and accuracy
print(batch_y.shape)
opt = sess.run(optimizer, feed_dict={x: batch_x,
y: batch_y})
loss, acc = sess.run([cost, accuracy], feed_dict={x: batch_x,
y: batch_y})
print("Iter " + str(i) + ", Loss= " + \
"{:.6f}".format(loss) + ", Training Accuracy= " + \
"{:.5f}".format(acc))
print("Optimization Finished!")
# Calculate accuracy for all 10000 mnist test images
test_acc,valid_loss = sess.run([accuracy,cost], feed_dict={x: test_X,y: test_Y})
train_loss.append(loss)
test_loss.append(valid_loss)
train_accuracy.append(acc)
test_accuracy.append(test_acc)
print("Testing Accuracy:","{:.5f}".format(test_acc))
summary_writer.close()
I have my kernel dying each time I run this code on GPU. The problem can not be cuda or cudnn related since I can run another code on GPU.
#define shapes
weight_shapes = [(8,8,4,32), (4,4,32,64), (3,3,64,64), (3136,512),
(512,action_size), (32), (64), (64), (512), (action_size)]
def conv2d(x, W, b, strides=1):
# Conv2D wrapper, with bias and relu activation
x = tf.nn.conv2d(x, W, strides=[1, strides, strides, 1], padding='VALID')
x = tf.nn.bias_add(x, b)
#x = tf.layers.batch_normalization(x,training = True,trainable = True,epsilon = 1e-5,name = 'batch_norm1')
return tf.nn.relu(x)
def dense(x, W, b):
return tf.add(tf.matmul(x, W), b)
def policy(inputs_, W):
with tf.name_scope("conv1"):
# Input is 84x84x4
conv1 = conv2d(inputs_, W[0], W[5], strides=4)
with tf.name_scope("conv2"):
conv2 = conv2d(conv1, W[1], W[6], strides=2)
with tf.name_scope("conv3"):
conv3 = conv2d(conv2, W[2], W[7], strides=1)
## --> [7, 7, 64]
with tf.name_scope("flatten"):
flatten = tf.contrib.layers.flatten(conv3)
## --> [3136]
with tf.name_scope("fc1"):
fc1 = tf.nn.relu(dense(flatten, W[3], W[8]))
with tf.name_scope("logits"):
logits = dense(fc1, W[4], W[9])
return logits
And the main part of code is:
################################
### build the network policy####
################################
class PGNetwork:
def __init__(self, state_size, action_size, learning_rate):
self.state_size = state_size
self.action_size = action_size
self.learning_rate = learning_rate
self.weights = [
tf.get_variable('wc1', shape = weight_shapes[0], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('wc2', shape = weight_shapes[1], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('wc3', shape = weight_shapes[2], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('wd1', shape = weight_shapes[3], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('wd2', shape = weight_shapes[4], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('bc1', shape = weight_shapes[5], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('bc2', shape = weight_shapes[6], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('bc3', shape = weight_shapes[7], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('bd1', shape = weight_shapes[8], initializer=tf.contrib.layers.xavier_initializer()),
tf.get_variable('bd2', shape = weight_shapes[9], initializer=tf.contrib.layers.xavier_initializer())
]
with tf.name_scope("inputs"):
# We create the placeholders
# *state_size means that we take each elements of state_size in tuple hence is like if we wrote
# [None, 84, 84, 4] #the first argument is related to batch size
self.inputs_= tf.placeholder(tf.float32, [None, *state_size], name="inputs_")
self.actions = tf.placeholder(tf.int32, [None, action_size], name="actions")
self.discounted_episode_rewards_ = tf.placeholder(tf.float32, [None, ], name="discounted_episode_rewards_")
self.flat_multiplier_tensor = tf.placeholder(tf.float32, shape = [None])
# Add this placeholder for having this variable in tensorboard
self.mean_reward_ = tf.placeholder(tf.float32, name="mean_reward")
with tf.variable_scope('PGNetwork'):
self.logits = policy(self.inputs_, self.weights)
with tf.name_scope("softmax"):
self.action_distribution = tf.nn.softmax(self.logits)
with tf.name_scope("sample_gradient"):
self.split_inputs = tf.unstack(self.inputs_, num = batch_size_zero_padded, axis=0)
self.split_actions = tf.unstack(self.actions, num = batch_size_zero_padded, axis = 0)
self.intermediate = [tf.expand_dims(self.split_inputs[i], 0) for i in range(batch_size_zero_padded)]
and then when I try to run the following code, kernel dies: The kernel appears to have died. It will restart automatically.
# Reset the graph
tf.reset_default_graph()
# Instantiate the PGNetwork
PGNetwork = PGNetwork(state_size, action_size, learning_rate)
# Initialize Session
sess = tf.Session()
init = tf.global_variables_initializer()
sess.run(init)
I would appreciate any idea on what might be going wrong! I am using python 3.6 with tensorflow-gpu 1.9.0.
I am new to Tensorflow and Machine Learning and trying out CNN using Tensorflow with my custom input data. But I am getting the error attached below.
The Data or Image Size is 28x28 with 15 Labels.
I am not getting the numpy reshape thing in this script or the error.
Help is highly appreciated.
import tensorflow as tf
import os
import skimage.data
import numpy as np
import random
def load_data(data_directory):
directories = [d for d in os.listdir(data_directory)
if os.path.isdir(os.path.join(data_directory, d))]
labels = []
images = []
for d in directories:
label_directory = os.path.join(data_directory, d)
file_names = [os.path.join(label_directory, f)
for f in os.listdir(label_directory)
if f.endswith(".jpg")]
for f in file_names:
images.append(skimage.data.imread(f))
labels.append(d)
print(str(d)+' Completed')
return images, labels
ROOT_PATH = "H:\Testing\TrainingData"
train_data_directory = os.path.join(ROOT_PATH, "Training")
test_data_directory = os.path.join(ROOT_PATH, "Testing")
print('Loading Data...')
images, labels = load_data(train_data_directory)
print('Data has been Loaded')
n_classes = 15
training_examples = 10500
test_examples = 4500
batch_size = 128
x = tf.placeholder('float', [None, 784])
y = tf.placeholder('float')
def conv2d(x, W):
return tf.nn.conv2d(x, W, strides=[1,1,1,1], padding='SAME')
def maxpool2d(x):
return tf.nn.max_pool(x, ksize=[1,2,2,1], strides=[1,2,2,1], padding='SAME')
def neural_network_model(x):
weights = {'W_Conv1':tf.Variable(tf.random_normal([5,5,1,32])),
'W_Conv2':tf.Variable(tf.random_normal([5,5,32,64])),
'W_FC':tf.Variable(tf.random_normal([7*7*64, 1024])),
'Output':tf.Variable(tf.random_normal([1024, n_classes]))}
biases = {'B_Conv1':tf.Variable(tf.random_normal([32])),
'B_Conv2':tf.Variable(tf.random_normal([64])),
'B_FC':tf.Variable(tf.random_normal([1024])),
'Output':tf.Variable(tf.random_normal([n_classes]))}
x = tf.reshape(x, shape=[-1,28,28,1])
conv1 = conv2d(x, weights['W_Conv1'])
conv1 = maxpool2d(conv1)
conv2 = conv2d(conv1, weights['W_Conv2'])
conv2 = maxpool2d(conv2)
fc = tf.reshape(conv2, [-1, 7*7*64])
fc = tf.nn.relu(tf.matmul(fc, weights['W_FC'])+biases['B_FC'])
output = tf.matmul(fc, weights['Output'])+biases['Output']
return output
def next_batch(num, data, labels):
idx = np.arange(0 , len(data))
np.random.shuffle(idx)
idx = idx[:num]
data_shuffle = [data[ i] for i in idx]
labels_shuffle = [labels[ i] for i in idx]
return np.asarray(data_shuffle), np.asarray(labels_shuffle)
def train_neural_network(x):
prediction = neural_network_model(x)
cost = tf.reduce_mean( tf.nn.softmax_cross_entropy_with_logits(logits=prediction, labels=y) )
optimizer = tf.train.AdamOptimizer().minimize(cost)
hm_epochs = 10
with tf.Session() as sess:
# OLD:
#sess.run(tf.initialize_all_variables())
# NEW:
sess.run(tf.global_variables_initializer())
for epoch in range(hm_epochs):
epoch_loss = 0
for _ in range(int(training_examples/batch_size)):
epoch_x, epoch_y = next_batch(batch_size, images, labels)
_, c = sess.run([optimizer, cost], feed_dict={x: epoch_x, y: epoch_y})
epoch_loss += c
print('Epoch', epoch, 'completed out of',hm_epochs,'loss:',epoch_loss)
correct = tf.equal(tf.argmax(prediction, 1), tf.argmax(y, 1))
accuracy = tf.reduce_mean(tf.cast(correct, 'float'))
print('Accuracy:',accuracy.eval({x: images, y: labels}))
print('Training Neural Network...')
train_neural_network(x)
What am I doing wrong? What is needed to be fixed and how do I fix the shape of numpy array?
If you look closely, you'll see that you have two x placeholders:
x = tf.placeholder('float', [None, 784]) # global
...
x = tf.reshape(x, shape=[-1,28,28,1]) # in neural_network_model
One of them is in the function scope, hence not visible in train_neural_network, so tensorflow takes the one with [?, 784] shape. You should get rid of one of them.
Also note that your training data has the rank 3, i.e. [batch_size, 28, 28], so it's not directly compatible with any of those placeholders.
To feed it into the first x, take epoch_x.reshape([-1, 784]). For the second placeholder (once you make it visible), take epoch_x.reshape([-1, 28, 28, 1]).
I have to finetune VGG.There are five convolutional layers and then three fully connected layers. Output from the last fully connected layer is the input of the loss function. Following is my code:
class vgg16:
def __init__(self, imgs1,imgs2, weights=None, sess=None):
self.imgs1 = imgs1
self.imgs2 = imgs2
with tf.variable_scope("siamese") as scope:
self.o1 = self.convlayers(imgs1)
self.fc_layers()
self.loss()
if weights is not None and sess is not None:
self.load_weights(weights, sess)
scope.reuse_variables()
self.o2 = self.convlayers(imgs2)
self.fc_layers()
self.loss()
if weights is not None and sess is not None:
self.load_weights(weights, sess)
#create loss function
def convlayers(self,imgs):
....
# conv1_2
with tf.name_scope('conv1_2') as scope:
......
# pool1
..
)
.....
# pool5
self.pool5 = tf.nn.max_pool(self.conv5_3,
ksize=[1, 2, 2, 1],
strides=[1, 2, 2, 1],
padding='SAME',
name='pool4')
def fc_layers(self):
# fc1
with tf.name_scope('fc1') as scope:
....
# fc2
with tf.name_scope('fc2') as scope:
...
# fc3
with tf.name_scope('fc3') as scope:
fc3w = tf.Variable(tf.truncated_normal([4096, 1000],
dtype=tf.float32,
stddev=1e-1), name='weights')
fc3b = tf.Variable(tf.constant(1.0, shape=[1000], dtype=tf.float32),
trainable=True, name='biases')
self.fc3l = tf.nn.bias_add(tf.matmul(self.fc2, fc3w), fc3b)
def load_weights(self, weight_file, sess):
weights = np.load(weight_file)
keys = sorted(weights.keys())
for i, k in enumerate(keys):
print i, k, np.shape(weights[k])
sess.run(self.parameters[i].assign(weights[k]))
def loss(self):
loss=tf.nn.l2_loss(self.fc3l)
self.train_step = tf.train.GradientDescentOptimizer(0.5).minimize(loss)
if __name__ == '__main__':
sess = tf.Session()
imgs1 = tf.placeholder(tf.float32, [None, 224, 224, 3])#jis size ka bhi imaeg hai usko 224x224 may kar diya or RGB chaeay hmay
imgs2 = tf.placeholder(tf.float32, [None, 224, 224, 3])
vgg = vgg16(imgs1,imgs2, 'vgg16_weights.npz', sess)
img1 = imread('laska.png', mode='RGB')
img1 = imresize(img1, (224, 224))
img2 = imread('laska2.jpg', mode='RGB')
img2 = imresize(img2,(224, 224))
prob = sess.run(vgg.train_step, feed_dict={vgg.imgs1: [img1],vgg.imgs2: [img2]})
print('loss is:')
print(prob)
The problem is that the output of prob is None. Kindly indicate what I am doing wrong.
PS: I am following siamese architecture. Input to both branches are different images here.
The op self.train_step does not return anything, it just calculates gradients and updates variables. See here.
What you need to do is to save reference to loss tensor in your vgg16 class like this:
self.loss=tf.nn.l2_loss(self.fc3l)
and then execute both train_step and loss operations in single sess.run:
_, loss_value = sess.run([vgg.train_step, vgg.loss], feed_dict=...)
print('loss is:')
print(loss_value)