correlation coefficient and cosine similarity

correlation_similarity.py

import numpy

def corr_percentage(a, b):
    # Ref:
    # - https://en.wikipedia.org/wiki/Pearson_product-moment_correlation_coefficient
    # - http://docs.scipy.org/doc/numpy/reference/generated/numpy.corrcoef.html
    #return 0.5 * numpy.corrcoef(a,b)[0][1] + 0.5
    return numpy.abs(numpy.corrcoef(a,b)[0][1])

def cosine_similarity(a, b):
    # Ref:
    # - https://en.wikipedia.org/wiki/Cosine_similarity
    ma = numpy.matrix(a, copy=False)
    mb = numpy.matrix(b, copy=False)
    #return 0.5 * (float(ma*mb.T)/(numpy.linalg.norm(ma)*numpy.linalg.norm(mb))) + 0.5
    return numpy.abs(float(ma*mb.T)/(numpy.linalg.norm(ma)*numpy.linalg.norm(mb)))


a = [1,2,3,4,5]
b = [1,3,4,4,5]


corr_percentage(a, b)

cosine_similarity(a, b)

Added cosine_similarity()

maybe change return value of corr_percentage()

return numpy.abs(numpy.corrcoef(a,b)[0][1])

abs the negative correlation?
maybe the cosine_similarity() also have to do the same thing...