## Mercurial > repos > shellac > sam_consensus_v3

### diff env/lib/python3.9/site-packages/networkx/algorithms/bipartite/redundancy.py @ 0:4f3585e2f14b draft default tip

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"planemo upload commit 60cee0fc7c0cda8592644e1aad72851dec82c959"

author | shellac |
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date | Mon, 22 Mar 2021 18:12:50 +0000 |

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--- /dev/null Thu Jan 01 00:00:00 1970 +0000 +++ b/env/lib/python3.9/site-packages/networkx/algorithms/bipartite/redundancy.py Mon Mar 22 18:12:50 2021 +0000 @@ -0,0 +1,111 @@ +"""Node redundancy for bipartite graphs.""" +from itertools import combinations + +from networkx import NetworkXError + +__all__ = ["node_redundancy"] + + +def node_redundancy(G, nodes=None): + r"""Computes the node redundancy coefficients for the nodes in the bipartite + graph `G`. + + The redundancy coefficient of a node `v` is the fraction of pairs of + neighbors of `v` that are both linked to other nodes. In a one-mode + projection these nodes would be linked together even if `v` were + not there. + + More formally, for any vertex `v`, the *redundancy coefficient of `v`* is + defined by + + .. math:: + + rc(v) = \frac{|\{\{u, w\} \subseteq N(v), + \: \exists v' \neq v,\: (v',u) \in E\: + \mathrm{and}\: (v',w) \in E\}|}{ \frac{|N(v)|(|N(v)|-1)}{2}}, + + where `N(v)` is the set of neighbors of `v` in `G`. + + Parameters + ---------- + G : graph + A bipartite graph + + nodes : list or iterable (optional) + Compute redundancy for these nodes. The default is all nodes in G. + + Returns + ------- + redundancy : dictionary + A dictionary keyed by node with the node redundancy value. + + Examples + -------- + Compute the redundancy coefficient of each node in a graph:: + + >>> from networkx.algorithms import bipartite + >>> G = nx.cycle_graph(4) + >>> rc = bipartite.node_redundancy(G) + >>> rc[0] + 1.0 + + Compute the average redundancy for the graph:: + + >>> from networkx.algorithms import bipartite + >>> G = nx.cycle_graph(4) + >>> rc = bipartite.node_redundancy(G) + >>> sum(rc.values()) / len(G) + 1.0 + + Compute the average redundancy for a set of nodes:: + + >>> from networkx.algorithms import bipartite + >>> G = nx.cycle_graph(4) + >>> rc = bipartite.node_redundancy(G) + >>> nodes = [0, 2] + >>> sum(rc[n] for n in nodes) / len(nodes) + 1.0 + + Raises + ------ + NetworkXError + If any of the nodes in the graph (or in `nodes`, if specified) has + (out-)degree less than two (which would result in division by zero, + according to the definition of the redundancy coefficient). + + References + ---------- + .. [1] Latapy, Matthieu, ClĂ©mence Magnien, and Nathalie Del Vecchio (2008). + Basic notions for the analysis of large two-mode networks. + Social Networks 30(1), 31--48. + + """ + if nodes is None: + nodes = G + if any(len(G[v]) < 2 for v in nodes): + raise NetworkXError( + "Cannot compute redundancy coefficient for a node" + " that has fewer than two neighbors." + ) + # TODO This can be trivially parallelized. + return {v: _node_redundancy(G, v) for v in nodes} + + +def _node_redundancy(G, v): + """Returns the redundancy of the node `v` in the bipartite graph `G`. + + If `G` is a graph with `n` nodes, the redundancy of a node is the ratio + of the "overlap" of `v` to the maximum possible overlap of `v` + according to its degree. The overlap of `v` is the number of pairs of + neighbors that have mutual neighbors themselves, other than `v`. + + `v` must have at least two neighbors in `G`. + + """ + n = len(G[v]) + # TODO On Python 3, we could just use `G[u].keys() & G[w].keys()` instead + # of instantiating the entire sets. + overlap = sum( + 1 for (u, w) in combinations(G[v], 2) if (set(G[u]) & set(G[w])) - {v} + ) + return (2 * overlap) / (n * (n - 1))