def train():
sparkUrl = 'spark://ubuntu02:7077'
file_path = 'hdfs://ubuntu02:9000/vectors/sentences_vector.csv'
hdfs_url = 'http://ubuntu02:50070'
user = '******'
# 用來分桶的參數(愈小桶越多)
r = 0.002
# 所有句向量集合
sc = get_conf(sparkUrl, 'LSH_train', "8g")
df = load_sentence_data_frame(sc, file_path)
# 隨機抽取一個向量v
v = df.sample(False, 0.1, seed=0).rdd.first()['_vector']
# 對每一個值算一個hash code: floor(dot(u,v) / r)
tmp = df.rdd.flatMap(
lambda x: {
Row(x['id'], x['sentence'], x['vector'],
TypeConverters.toInt(np.floor(x['_vector'].dot(v) / r)))
})
# 重新命名
df = SQLContext(sc).createDataFrame(tmp) \
.selectExpr("_1 as id",
"_2 as sentence",
"_3 as vector",
"_4 as hash_code")
# 保存dataframe以加快速度
df.persist()
# 顯示各組分類情況
summary = df.groupby("hash_code").count()
summary.persist()
# 取得所有桶的名稱
names = summary.rdd.map(lambda x: x.hash_code).collect()
# 歷遍每個分組
for name in names:
print('save to ' + str(name))
tmp = df.filter(df['hash_code'] == name)
# 刪除hash_code欄位以節省空間
tmp = tmp.drop('hash_code')
# 寫入hdfs(這個操作巨慢)
tmp.toPandas().to_csv('/home/hadoop/new/' + str(name) + '.csv',
sep=',',
index=False,
encoding='utf-8')
with open('/home/hadoop/new/meta.txt', 'w') as f:
f.write('vector(v):\n')
for e in v:
f.write(str(e) + ',')
f.write('\nnames:\n')
for name in names:
f.write(str(name) + ',')
print('all done!!')
return
