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我有2RDD,我想在這兩個rdd之間乘以元素。乘以SparseVectors元素明智
比方說,我有以下RDD(例如):
a = ((1,[0.28,1,0.55]),(2,[0.28,1,0.55]),(3,[0.28,1,0.55]))
aRDD = sc.parallelize(a)
b = ((1,[0.28,0,0]),(2,[0,0,0]),(3,[0,1,0]))
bRDD = sc.parallelize(b)
可以看出,b
是稀疏的,我想避免乘零值與另一個值。我做了以下情況:
from pyspark.mllib.linalg import Vectors
def create_sparce_matrix(a_list):
length = len(a_list)
index = [i for i ,e in enumerate(a_list) if e !=0]
value = [e for i ,e in enumerate(a_list) if e !=0]
sv1 = Vectors.sparse(length,index,value)
return sv1
brdd = b.map(lambda (ids,a_list):(ids,create_sparce_matrix(a_list)))
和乘法:
combinedRDD = ardd + brdd
result = combinedRDD.reduceByKey(lambda a,b:[c*d for c,d in zip(a,b)])
看來我不能繁殖的sparce在RDD列表。有沒有辦法做到這一點?或者當兩個RDD中的一個具有很多零值時,用另一種有效的方法來乘以元素?你可以處理這個