wanna_bi_projection.py

import pandas as pd
import numpy as np


def wannabe_projection(df):
    '''
    https://stats.stackexchange.com/questions/142132/is-this-a-valid-method-for-unipartite-projection-of-a-bipartite-graph
    '''
    n_samples = df.shape[0]
    res = np.zeros((n_samples, n_samples))
    index = df.index
    df = df.T
    i = 0
    while i < n_samples:
        j = 0
        while j < n_samples:
            if i == j:
                res[i][j] = 0
            else:
                res[i][j] = df[[index[i], index[j]]].min(axis=1).sum()
            j += 1
        i += 1
    return pd.DataFrame(res, index=df.index, columns=df.index)


if __name__ == '__main__':
    # X = np.array([[1, 8, 3], [5, 2, 0], [0, 4, 2]])
    # df = pd.DataFrame(X, index=['A','B','C'], columns=['x','y','z'])
    X = np.array([[0,1,3],[2,4,6]])
    df = pd.DataFrame(X, index=['A','B'], columns=['x','y','z'])
    print wannabe_projection(df)