HELP why loss keep a high value base flower dataset

[juzhitao]

I user flower dataset（5 classes and 2500 for train and 500 for val） to create tfrecords file and as input to train,but loss can not reduce and validation acc keep 20% , it is my code have some bug when read tfrecords?

import tensorflow as tf
from tqdm import tqdm
import numpy as np
from utils import load_obj
import matplotlib.pyplot as plt

class Train:
"""Trainer class for the CNN.
It's also responsible for loading/saving the model checkpoints from/to experiments/experiment_name/checkpoint_dir"""

def __init__(self, sess, model, data, summarizer):
    self.sess = sess
    self.model = model
    self.args = self.model.args
    self.saver = tf.train.Saver(max_to_keep=self.args.max_to_keep,
                                keep_checkpoint_every_n_hours=10,
                                save_relative_paths=True)
    # Summarizer references
    self.data = data
    self.summarizer = summarizer

    # Initializing the model
    self.init = None
    self.__init_model()

    # Loading the model checkpoint if exists
    self.__load_imagenet_weights()
    self.__load_model()
    IMAGE_SIZE = 224
    NUM_CLASSES = 5

############################################################################################################
# Model related methods
def __init_model(self):
    print("Initializing the model...")
    self.init = tf.group(tf.global_variables_initializer())
    self.sess.run(self.init)
    print("Model initialized\n\n")

def save_model(self):
    """
    Save Model Checkpoint
    :return:
    """
    print("Saving a checkpoint")
    self.saver.save(self.sess, self.args.checkpoint_dir, self.model.global_step_tensor)
    print("Checkpoint Saved\n\n")

def __load_model(self):
    latest_checkpoint = tf.train.latest_checkpoint(self.args.checkpoint_dir)
    if latest_checkpoint:
        print("Loading model checkpoint {} ...\n".format(latest_checkpoint))
        self.saver.restore(self.sess, latest_checkpoint)
        print("Checkpoint loaded\n\n")
    else:
        print("First time to train!\n\n")

def __load_imagenet_weights(self):
    variables = tf.get_collection(tf.GraphKeys.GLOBAL_VARIABLES)

    print("No pretrained ImageNet weights exist. Skipping...\n\n")

############################################################################################################
# Train and Test methods 

def read_and_decode(self,filename_queue):
    reader = tf.TFRecordReader()
    _, serialized_example = reader.read(filename_queue)
    features = tf.parse_single_example(
        serialized_example,
        # Defaults are not specified since both keys are required.
            features={
            'image': tf.FixedLenFeature([], tf.string),
            'target': tf.FixedLenFeature([], tf.int64),
        })

    # Convert from a scalar string tensor (whose single string has
    image = tf.image.decode_jpeg(features['image'], channels=3)
    image = tf.image.convert_image_dtype(image, tf.float32)
    image = tf.image.resize_image_with_crop_or_pad(image, 224, 224)
    image = tf.clip_by_value(image, 0.0, 1.0)

    # Convert label from a scalar uint8 tensor to an int32 scalar.
    label = tf.cast(features['target'], tf.int32)

    return image, label

def train(self):   
   
    filename_queue = tf.train.string_input_producer(["/home/coolpad/juzhitao/shufflenet/mg2033/ShuffleNet/train1.tfrecords"])
    #train data
    image, label = self.read_and_decode(filename_queue)
    
    images, labels = tf.train.shuffle_batch([image, label], batch_size=50, num_threads=2,capacity=2500,min_after_dequeue=250)        
    
    init_op = tf.group(tf.global_variables_initializer(),tf.local_variables_initializer())
    self.sess.run(init_op)
    
    coord = tf.train.Coordinator()
    threads = tf.train.start_queue_runners(sess=self.sess, coord=coord)  
    
    for cur_epoch in range(self.model.global_epoch_tensor.eval(self.sess) + 1, self.args.num_epochs + 1, 1):
        # Initialize tqdm          
       
        num_iterations = self.args.train_data_size // self.args.batch_size
        print("num_iterations:::::::::::",num_iterations,'      ','train_data_size=',self.args.train_data_size ,'batch_size:', self.args.batch_size)
        #tqdm_batch = tqdm([self.data.X_train,self.data.y_train], total=num_iterations,
        #                  desc="Epoch-" + str(cur_epoch) + "-")
                   

        # Initialize the current iterations
        cur_iteration = 0

        # Initialize classification accuracy and loss lists
        loss_list = []
        acc_list = []

    
        # Loop by the number of iterations
        print("#####################################cur_epoch==",cur_epoch)
        #for self.data.X_train, self.data.y_train in tqdm_batch:
        for step in tqdm(range(0,  num_iterations),initial=1, total=num_iterations):
            # Get the current iteration for summarizing it
            cur_step = self.model.global_step_tensor.eval(self.sess)
            
            image_train, lable_train = self.sess.run([images,labels])               
            #print(image_train)
            # Feed this variables to the network
            feed_dict = {self.model.X: images,
                         self.model.y: labels,
                         self.model.is_training: True
                         }
            # Run the feed_forward
            _, loss, acc = self.sess.run(
                [self.model.train_op, self.model.loss, self.model.accuracy],
                feed_dict=feed_dict)
            # Append loss and accuracy
            loss_list += [loss]
            acc_list += [acc]

            # Update the Global step
            self.model.global_step_assign_op.eval(session=self.sess,
                                                  feed_dict={self.model.global_step_input: cur_step + 1})

            #self.summarizer.add_summary(cur_step, summaries_merged=summaries_merged)

            if step >= num_iterations - 1:
                avg_loss = np.mean(loss_list)
                avg_acc = np.mean(acc_list)
                # summarize
                #summaries_dict = dict()
                #summaries_dict['loss'] = avg_loss
                #summaries_dict['acc'] = avg_acc

                # summarize
                #self.summarizer.add_summary(cur_step, summaries_dict=summaries_dict)

                # Update the Current Epoch tensor
                self.model.global_epoch_assign_op.eval(session=self.sess,
                                                       feed_dict={self.model.global_epoch_input: cur_epoch + 1})

                # Print in console
                #tqdm_batch.close()
                print("Epoch-" + str(cur_epoch) + " | " + "loss: " + str(avg_loss) + " -" + " acc: " + str(
                    avg_acc)[
                                                                                                       :7])
                # Break the loop to finalize this epoch
                #break

            # Update the current iteration
            cur_iteration += 1

        # Save the current checkpoint
        if cur_epoch % self.args.save_model_every == 0 and cur_epoch != 0:
            self.save_model()

        # Test the model on validation or test data
        if cur_epoch % self.args.test_every == 0:
            self.test('val')
            
    coord.request_stop()
    coord.join(threads)               

def test(self, test_type='val'):
   
    filename_queue = tf.train.string_input_producer(["/home/coolpad/juzhitao/shufflenet/mg2033/ShuffleNet/val1.tfrecords"])
    #val data
    image, label = self.read_and_decode(filename_queue)
    
    images, labels = tf.train.shuffle_batch([image, label], batch_size=50, num_threads=2,capacity=200,min_after_dequeue=50)        
    
    init_op = tf.group(tf.global_variables_initializer(),tf.local_variables_initializer())
    self.sess.run(init_op)
    
    coord = tf.train.Coordinator()
    threads = tf.train.start_queue_runners(sess=self.sess, coord=coord) 
    
    
    num_iterations = self.args.test_data_size // self.args.batch_size
    #tqdm_batch = tqdm(self.data.generate_batch(type=test_type), total=num_iterations,
    #                  desc='Testing')
   
    
    # Initialize classification accuracy and loss lists
    loss_list = []
    acc_list = []
    cur_iteration = 0

    #for X_batch, y_batch in tqdm_batch:
    for step in tqdm(range(0,  num_iterations),initial=1, total=num_iterations):
    
        image_val, label_val = self.sess.run([images,labels])
        # Feed this variables to the network
        feed_dict = {self.model.X: image_val,
                     self.model.y: label_val,
                     self.model.is_training: False
                     }
        # Run the feed_forward
        loss, acc = self.sess.run(
            [self.model.loss, self.model.accuracy],
            feed_dict=feed_dict)

        # Append loss and accuracy
        loss_list += [loss]
        acc_list += [acc]

        if step >= num_iterations - 1:
            avg_loss = np.mean(loss_list)
            avg_acc = np.mean(acc_list)
            print('Test results | test_loss: ' + str(avg_loss) + ' - test_acc: ' + str(avg_acc)[:7])
            #break

        cur_iteration += 1