Coverage for src/causalspyne/erdo_renyi_plp.py: 100%

1""" 

2concrete class to generate simple DAGs 

3 

4""" 

5import numpy as np 

6 

7 

8class Erdos_Renyi_PLP: 

9 """ 

10 uniformly (w.r.t. each edge) decide if the edge will exist w.r.t. a prob. 

11 threshold 

12 trick: PLP^T to ensure a DAG, L is lower triangular (topological order) 

13 P is permutation, P permute the labels 

14 (i,j) entry indicate j->i 

15 row permutation (i,j), (k,j) becomes (k,j) (i,j) 

16 column permutation 

17 """ 

18 

19 def __init__(self, rng): 

20 self.rng = rng 

21 

22 def __call__(self, num_nodes, degree): 

23 prob = float(degree) / (num_nodes - 1) 

24 # lower triagular, k=-1 is the lower off diagonal 

25 mat_lower_triangle_binary = np.tril( 

26 (self.rng.random((num_nodes, num_nodes)) < prob 

27 ).astype(float), k=-1 

28 ) 

29 # permutes first axis only 

30 mat_perm = self.rng.permutation(np.eye(num_nodes, num_nodes)) 

31 mat_b_permuted = mat_perm.T.dot( 

32 mat_lower_triangle_binary).dot(mat_perm) 

33 return mat_b_permuted