mxnet深度学习实战：跑自己的数据实验和一些问题总结

用mxnet跑自己的数据

1 数据准备

   参考  http://blog.csdn.net/a350203223/article/details/50263737   把数据转换成 REC 模式。

   备注： make_list.py  可以自动生成 train 和 val 的 lst文件。  可使用参数  --train_ratio=XXX 

2 跑数据

  参考mxnet/example/image-classification里面train_cifar10.py 和 symbol_inception-bn-28-small.py

  symbol文件主要用来保存网络结构

  一个简单的3层CNN网络

symbol_UCM.py

import find_mxnet
import mxnet as mx


def get_symbol(num_classes = 21):
    data = mx.symbol.Variable('data')
    # first conv
    conv1 = mx.symbol.Convolution(data=data, kernel=(3,3), num_filter=128)
    bn1 = mx.symbol.BatchNorm(data=conv1)
    relu1 = mx.symbol.Activation(data=bn1, act_type="relu")
    pool1 = mx.symbol.Pooling(data=relu1, pool_type="max",
              kernel=(5,5), stride=(3,3))
    # second conv
    conv2 = mx.symbol.Convolution(data=pool1, kernel=(3,3), num_filter=196)
    bn2 = mx.symbol.BatchNorm(data=conv2)
    relu2 = mx.symbol.Activation(data=bn2, act_type="relu")
    pool2 = mx.symbol.Pooling(data=relu2, pool_type="max",
              kernel=(3,3), stride=(2,2))
    # second conv
    conv3 = mx.symbol.Convolution(data=pool2, kernel=(3,3), num_filter=196)
    bn3 = mx.symbol.BatchNorm(data=conv3)
    relu3 = mx.symbol.Activation(data=bn3, act_type="relu")
    pool3 = mx.symbol.Pooling(data=relu3, pool_type="max",
              kernel=(2,2), stride=(2,2), name="final_pool")
    # first fullc
    flatten = mx.symbol.Flatten(data=pool3)
    fc1 = mx.symbol.FullyConnected(data=flatten, num_hidden=420)
    relu4 = mx.symbol.Activation(data=fc1, act_type="relu")
    # second fullc
    fc2 = mx.symbol.FullyConnected(data=relu4, num_hidden=num_classes)
    # loss
    softmax = mx.symbol.SoftmaxOutput(data=fc2, name='softmax')
    return softmax

   train_UCM.py

   

import find_mxnet
import mxnet as mx
import argparse
import os, sys
import train_model

parser = argparse.ArgumentParser(description='train an image classifer on UCMnet')
parser.add_argument('--network', type=str, default='UCM_128_BN3layer',
                    help = 'the cnn to use')
parser.add_argument('--data-dir', type=str, default='/home/panda/Ureserch/data/Scene/UCM/',
                    help='the input data directory')
parser.add_argument('--gpus', type=str, default='0',
                    help='the gpus will be used, e.g "0,1,2,3"')
parser.add_argument('--num-examples', type=int, default=1680,
                    help='the number of training examples')
parser.add_argument('--batch-size', type=int, default=64,
                    help='the batch size')
parser.add_argument('--lr', type=float, default=.01,
                    help='the initial learning rate')
parser.add_argument('--lr-factor', type=float, default=.94,
                    help='times the lr with a factor for every lr-factor-epoch epoch')
parser.add_argument('--lr-factor-epoch', type=float, default=5,
                    help='the number of epoch to factor the lr, could be .5')
parser.add_argument('--model-prefix', type=str,
                    help='the prefix of the model to load/save')
parser.add_argument('--num-epochs', type=int, default=80,
                    help='the number of training epochs')
parser.add_argument('--load-epoch', type=int,
                    help="load the model on an epoch using the model-prefix")
parser.add_argument('--kv-store', type=str, default='local',
                    help='the kvstore type')
# 存放训练信息，用来画 training curve
parser.add_argument('--log-file', type=str,default="xxx",
                    help='the name of log file')
parser.add_argument('--log-dir', type=str, default="/xxx/xxx/xxx/",
                    help='directory of the log file')
args = parser.parse_args() 

# network
import importlib
net = importlib.import_module('symbol_' + args.network).get_symbol(21)



# data   如果没有 image-mean ， 会自动计算，存放于 args.data_dir + "xxx.bin"
def get_iterator(args, kv):
    data_shape = (3, 109, 109)

    train = mx.io.ImageRecordIter(
        path_imgrec = args.data_dir + "xxx.rec",
        mean_img    = args.data_dir + "xxx.bin",        
        data_shape  = data_shape,
        batch_size  = args.batch_size,
        rand_crop   = True,
        rand_mirror = True,
        num_parts   = kv.num_workers,
        part_index  = kv.rank)

    val = mx.io.ImageRecordIter(
        path_imgrec = args.data_dir + "xxxrec",
        mean_img    = args.data_dir + "xxx.bin",
        rand_crop   = False,
        rand_mirror = False,
        data_shape  = data_shape,
        batch_size  = args.batch_size,
        num_parts   = kv.num_workers,
        part_index  = kv.rank)

    return (train, val)


# train
train_model.fit(args, net, get_iterator)

3.  利用 log 画 training和val曲线

    需用到matplotlib，提前安装

import matplotlib.pyplot as plt
import numpy as np
import re
import argparse

parser = argparse.ArgumentParser(description='Parses log file and generates train/val curves')
parser.add_argument('--log-file', type=str,default="/home/panda/Ureserch/mxnet_panda/UCM_EXP/UCM_128_log_4",
                    help='the path of log file')
args = parser.parse_args()


TR_RE = re.compile('.*?]\sTrain-accuracy=([\d\.]+)')
VA_RE = re.compile('.*?]\sValidation-accuracy=([\d\.]+)')

log = open(args.log_file).read()

log_tr = [float(x) for x in TR_RE.findall(log)]
log_va = [float(x) for x in VA_RE.findall(log)]
idx = np.arange(len(log_tr))

plt.figure(figsize=(8, 6))
plt.xlabel("Epoch")
plt.ylabel("Accuracy")
plt.plot(idx, log_tr, 'o', linestyle='-', color="r",
         label="Train accuracy")

plt.plot(idx, log_va, 'o', linestyle='-', color="b",
         label="Validation accuracy")

plt.legend(loc="best")
plt.xticks(np.arange(min(idx), max(idx)+1, 5))
plt.yticks(np.arange(0, 1, 0.2))
plt.ylim([0,1])
plt.show()

4. 保存训练好的模型

  在  train_model.py 加入如下代码，训练完成后保存

    prefix = 'UCM_MODEL'
    iteration = args.num_epochs
    model.save(prefix, iteration)

5. 利用保存的模型进行predict

 predict_UCM.py

import find_mxnet
import mxnet as mx
import logging
import argparse
import os, sys
import train_model
import numpy as np

# 这里用的 mxnet 的 imanet训练的 Inception模型， 其他模型同理
prefix = '/home/panda/Ureserch/mxnet_panda/inception-21k model/Inception'
iteration = 9
model_load = mx.model.FeedForward.load(prefix, iteration)
data_shape = (3, 224, 224)

# 数据准备  batch_size = 1.  
val = mx.io.ImageRecordIter(
        path_imgrec = '/xxx/xxx/' + "xxx.rec",
        mean_img    = '/xxx/xxx/' + "xxx.bin",
        rand_crop   = False,
        rand_mirror = False,
        data_shape  = data_shape,
        batch_size  = 1)

[prob, data1, label1] = model_load.predict(val, return_data=True)

6 利用 pretrain模型提取任意层特征

feature_extraction.py

模型和数据准备如 step.5， 还是

internals = model_load.symbol.get_internals()
# 记住要提取特征的那一层的名字。 我这是 flatten 。 
fea_symbol = internals["flatten_output"]
feature_extractor = mx.model.FeedForward(ctx=mx.gpu(), symbol=fea_symbol, numpy_batch_size=1,
                                         arg_params=model_load.arg_params, aux_params=model_load.aux_params,
                                         allow_extra_params=True)
[val_feature, valdata, vallabel]= feature_extractor.predict(val, return_data=True)

利用 scipy 保存 为 matlab格式 。毕竟matlab简单好操 
import scipy.io as sio
sio.savemat('/xxx/xxx.mat', {'val_feature':val_feature})

7 利用 pretrain 模型来初始化你的网络参数。

   再续