clusters.py 文件源码

def pearson(v1,v2):
    sum1 = sum(v1)
    sum2 = sum(v2)

    sum1Sq = sum([pow(v,2) for v in v1])
    sum2Sq = sum([pow(v,2) for v in v2])

    length = len(v1) if len(v1)<len(v2)  else len(v2)
    pSum = sum([v1[i]*v2[i] for i in range(length)])

    numerator = pSum-sum1*sum2/len(v1)
    denominator = sqrt(sum1Sq-pow(sum1,2)/len(v1))*(sum2Sq-pow(sum2,2)/len(v1))
    if denominator==0:
        return 0

    return 1-numerator/denominator