def random_partition(n,n_data):
    all_idxs = numpy.arange( n_data )
    numpy.random.shuffle(all_idxs)
    idxs1 = all_idxs[:n]
    idxs2 = all_idxs[n:]
    return idxs1, idxs2
return n random rows of data (and also the other len(data)-n rows)
dataset/ETHPy150Open jesolem/PCV/PCV/tools/ransac.py/random_partition