传统方式需要10s，dat方式需要0.6s
import os
import time
import torch
import random
from common.coco_dataset import COCODataset
def gen_data(batch_size,data_path,target_path):
os.makedirs(target_path,exist_ok=True)
dataloader = torch.utils.data.DataLoader(COCODataset(data_path,
(352, 352),
is_training=False, is_scene=True),
batch_size=batch_size,
shuffle=False, num_workers=0, pin_memory=False,
drop_last=True) # DataLoader
start = time.time()
for step, samples in enumerate(dataloader):
images, labels, image_paths = samples["image"], samples["label"], samples["img_path"]
print("time", images.size(0), time.time() - start)
start = time.time()
# torch.save(samples,target_path+ '/' + str(step) + '.dat')
print(step)
def cat_100(target_path,batch_size=100):
paths = os.listdir(target_path)
li = [i for i in range(len(paths))]
random.shuffle(li)
images = []
labels = []
image_paths = []
start = time.time()
for i in range(len(paths)):
samples = torch.load(target_path + str(li[i]) + ".dat")
image, label, image_path = samples["image"], samples["label"], samples["img_path"]
images.append(image.cuda())
labels.append(label.cuda())
image_paths.append(image_path)
if i % batch_size == batch_size - 1:
images = torch.cat((images), 0)
print("time", images.size(0), time.time() - start)
images = []
labels = []
image_paths = []
start = time.time()
i += 1
if __name__ == '__main__':
os.environ["CUDA_VISIBLE_DEVICES"] = '3'
batch_size=320
# target_path='d:/test_1000/'
target_path='d:\img_2/'
data_path = r'D:\dataset\origin_all_datas\_2train'
gen_data(batch_size,data_path,target_path)
# get_data(target_path,batch_size)
# cat_100(target_path,batch_size)
这个读取数据也比较快：320 batch_size 450ms
def cat_100(target_path,batch_size=100):
paths = os.listdir(target_path)
li = [i for i in range(len(paths))]
random.shuffle(li)
images = []
labels = []
image_paths = []
start = time.time()
for i in range(len(paths)):
samples = torch.load(target_path + str(li[i]) + ".dat")
image, label, image_path = samples["image"], samples["label"], samples["img_path"]
images.append(image)#.cuda())
labels.append(label)#.cuda())
image_paths.append(image_path)
if i % batch_size < batch_size - 1:
i += 1
continue
i += 1
images = torch.cat(([image.cuda() for image in images]), 0)
print("time", images.size(0), time.time() - start)
images = []
labels = []
image_paths = []
start = time.time()
补充：pytorch数据加载和处理问题解决方案
最近跟着pytorch中文文档学习遇到一些小问题，已经解决，在此对这些错误进行记录：
在读取数据集时报错：
AttributeError: 'Series' object has no attribute 'as_matrix'
在显示图片是时报错：
ValueError: Masked arrays must be 1-D
显示单张图片时figure一闪而过
在显示多张散点图的时候报错：
TypeError: show_landmarks() got an unexpected keyword argument 'image'
解决方案
主要问题在这一行： 最终目的是将Series转为Matrix，即调用np.mat即可完成。
修改前
landmarks =landmarks_frame.iloc[n, 1:].as_matrix()
修改后
landmarks =np.mat(landmarks_frame.iloc[n, 1:])
打散点的x和y坐标应该均为向量或列表，故将landmarks后使用tolist()方法即可
修改前
plt.scatter(landmarks[:,0],landmarks[:,1],s=10,marker='.',c='r')
修改后
plt.scatter(landmarks[:,0].tolist(),landmarks[:,1].tolist(),s=10,marker='.',c='r')
前面使用plt.ion()打开交互模式，则后面在plt.show()之前一定要加上plt.ioff()。这里直接加到函数里面，避免每次plt.show()之前都用plt.ioff()
修改前
def show_landmarks(imgs,landmarks): '''显示带有地标的图片''' plt.imshow(imgs) plt.scatter(landmarks[:,0].tolist(),landmarks[:,1].tolist(),s=10,marker='.',c='r')#打上红色散点 plt.pause(1)#绘图窗口延时
修改后
def show_landmarks(imgs,landmarks): '''显示带有地标的图片''' plt.imshow(imgs) plt.scatter(landmarks[:,0].tolist(),landmarks[:,1].tolist(),s=10,marker='.',c='r')#打上红色散点 plt.pause(1)#绘图窗口延时 plt.ioff()
网上说对于字典类型的sample可通过 **sample的方式获取每个键下的值，但是会报错，于是把输入写的详细一点，就成功了。
修改前
show_landmarks(**sample)
修改后
show_landmarks(sample['image'],sample['landmarks'])
以上为个人经验，希望能给大家一个参考，也希望大家多多支持。如有错误或未考虑完全的地方，望不吝赐教。
