Fix random hypergraph

xgi/core/dihypergraph.py

@@ -599,7 +599,7 @@ def add_edges_from(self, ebunch_to_add, **attr):
             i.e. you cannot mix different formats.  The iterables containing edge
             members cannot be strings.
 
-        attr : \*\*kwargs, optional
+        **attr : kwargs, optional
             Additional attributes to be assigned to all edges. Attribues specified via
             `ebunch_to_add` take precedence over `attr`.
 

xgi/core/hypergraph.py

@@ -633,7 +633,7 @@ def add_edges_from(self, ebunch_to_add, **attr):
             the same length, i.e. you cannot mix different formats.  The iterables
             containing edge members cannot be strings.
 
-        attr : \*\*kwargs:, optional
+        **attr : kwargs, optional
             Additional attributes to be assigned to all edges. Attribues specified via
             `ebunch_to_add` take precedence over `attr`.
 

xgi/core/simplicialcomplex.py

@@ -400,7 +400,7 @@ def add_simplices_from(self, ebunch_to_add, max_order=None, **attr):
             Maximal dimension of simplices to add. If None (default), adds all
             simplices.  If int, and `ebunch_to_add` contains simplices of order >
             `max_order`, creates and adds all its subfaces up to `max_order`.
-        attr : \*\*kwargs, optional
+        **attr : kwargs, optional
             Additional attributes to be assigned to all simplices. Attribues specified
             via `ebunch_to_add` take precedence over `attr`.
 

xgi/generators/random.py

@@ -5,12 +5,13 @@
 import warnings
 from collections import defaultdict
 from itertools import combinations
+from warnings import warn
 
 import numpy as np
-from scipy.special import comb
 
 from .classic import empty_hypergraph
 from .lattice import ring_lattice
+from .uniform import uniform_erdos_renyi_hypergraph
 
 __all__ = [
     "random_hypergraph",
@@ -20,15 +21,15 @@
 ]
 
 
-def random_hypergraph(N, ps, order=None, seed=None):
+def fast_random_hypergraph(n, ps, order=None, seed=None):
     """Generates a random hypergraph
 
     Generate N nodes, and connect any d+1 nodes
     by a hyperedge with probability ps[d-1].
 
     Parameters
     ----------
-    N : int
+    n : int
         Number of nodes
     ps : list of float
         List of probabilities (between 0 and 1) to create a
@@ -50,24 +51,29 @@ def random_hypergraph(N, ps, order=None, seed=None):
     ----------
     Described as 'random hypergraph' by M. Dewar et al. in https://arxiv.org/abs/1703.07686
 
+    See Also
+    --------
+    random_hypergraph
+
     Example
     -------
     >>> import xgi
-    >>> H = xgi.random_hypergraph(50, [0.1, 0.01])
+    >>> H = xgi.fast_random_hypergraph(50, [0.1, 0.01])
 
     """
-    if seed is not None:
-        np.random.seed(seed)
+    ps = np.array(ps)
 
     if order is not None:
         if len(ps) != 1:
             raise ValueError("ps must contain a single element if order is an int")
 
-    if (np.any(np.array(ps) < 0)) or (np.any(np.array(ps) > 1)):
+    if (ps < 0).any() or (ps > 1).any():
         raise ValueError("All elements of ps must be between 0 and 1 included.")
 
-    nodes = range(N)
-    hyperedges = []
+    nodes = range(n)
+
+    H = empty_hypergraph()
+    H.add_nodes_from(nodes)
 
     for i, p in enumerate(ps):
 
@@ -76,13 +82,74 @@ def random_hypergraph(N, ps, order=None, seed=None):
         else:
             d = i + 1  # order, ps[0] is prob of edges (d=1)
 
-        potential_edges = combinations(nodes, d + 1)
-        n_comb = comb(N, d + 1, exact=True)
-        mask = np.random.random(size=n_comb) <= p  # True if edge to keep
+        size = d + 1
+        if p > 0:
+            h_uniform = uniform_erdos_renyi_hypergraph(n, size, p, seed=seed)
+            H << h_uniform
+
+    return H
+
+
+def random_hypergraph(N, ps, seed=None):
+    """Generates a random hypergraph
+
+    Generate N nodes, and connect any d+1 nodes
+    by a hyperedge with probability ps[d-1].
+
+    Parameters
+    ----------
+    N : int
+        Number of nodes
+    ps : list of float
+        List of probabilities (between 0 and 1) to create a
+        hyperedge at each order d between any d+1 nodes. For example,
+        ps[0] is the wiring probability of any edge (2 nodes), ps[1]
+        of any triangles (3 nodes).
+    seed : integer, random_state, or None (default)
+            Indicator of random number generation state.
+
+    Returns
+    -------
+    Hypergraph object
+        The generated hypergraph
+
+    References
+    ----------
+    Described as 'random hypergraph' by M. Dewar et al. in https://arxiv.org/abs/1703.07686
+
+    Warns
+    -----
+    warnings.warn
+        Because `fast_random_hypergraph` is a much faster method for generating random hypergraphs.
+
+    See Also
+    --------
+    fast_random_hypergraph
+
+    Example
+    -------
+    >>> import xgi
+    >>> H = xgi.random_hypergraph(50, [0.1, 0.01])
+
+    """
+    warn("This method is much slower than fast_random_hypergraph")
+    if seed is not None:
+        random.seed(seed)
+
+    if (np.any(np.array(ps) < 0)) or (np.any(np.array(ps) > 1)):
+        raise ValueError("All elements of ps must be between 0 and 1 included.")
+
+    nodes = range(N)  # list(G.nodes())
+    hyperedges = []  # hyperedges = list(G.edges())
+
+    for i, p in enumerate(ps):
+        d = i + 1  # order, ps[0] is prob of edges (d=1)
 
-        edges_to_add = [e for e, val in zip(potential_edges, mask) if val]
+        for hyperedge in combinations(nodes, d + 1):
+            if random.random() <= p:
+                hyperedges.append(hyperedge)
 
-        hyperedges += edges_to_add
+    hyperedges += [[i] for i in nodes]  # add singleton edges
 
     H = empty_hypergraph()
     H.add_nodes_from(nodes)