创建 LMDB 数据

import sys
import numpy as np
import lmdb

caffe_root = '/home/amax/xyc/caffe-master/'
sys.path.insert(0, caffe_root + 'python')
import caffe

N = 40

X = np.zeros((N, 3, 32, 32), dtype=np.uint8)
y = np.zeros(N, dtype=np.int64)

map_size = X.nbytes * 10

env = lmdb.open('mylmdb', map_size=map_size)

with env.begin(write=True) as txn:
# txn is a Transaction object
for i in range(N):
datum = caffe.proto.caffe_pb2.Datum()
datum.channels = X.shape[1]
datum.height = X.shape[2]
datum.width = X.shape[3]
datum.data = X[i].tobytes()  # or .tostring() if numpy < 1.9
datum.label = int(y[i])
str_id = '{:08}'.format(i)

# The encode is only essential in Python 3
txn.put(str_id.encode('ascii'), datum.SerializeToString())