Add a sketch of lattice generation - half way

Very functional, very explicit node names - working so far

abp/lattices.py

@@ -0,0 +1,44 @@
+import networkx as nx
+from abp.fancy import GraphState
+
+def fast_union(graphs):
+    """ Assumes that all graphs are completely independent and uniquely labelled """
+    output = nx.Graph()
+    output.node = dict(i for g in graphs for i in g.node.items())
+    output.adj = dict(i for g in graphs for i in g.adj.items())
+    return output
+
+def relabel(g, label):
+    """ Shorthand relabel """
+    return nx.relabel_nodes(g, lambda x: (label, x))
+
+def fuse(a, b, na, nb):
+    """ Deterministic fusion for testing purposes """
+    psi = fast_union((a, b))
+    neighbors_a, neighbors_b = psi.neighbors(na), psi.neighbors(nb)
+    new_edges = ((i, j) for i in neighbors_a for j in neighbors_b if i != j)
+    psi.add_edges_from(new_edges)
+    psi.remove_nodes_from((na, nb))
+    return psi
+
+def ghz(label):
+    """ A 3-GHZ state """
+    psi = nx.Graph(((0, 1), (1, 2)))
+    return relabel(psi, label)
+
+def microcluster(label):
+    """ A microcluster """
+    psi = fuse(ghz(0), ghz(1), (0, 1), (1, 0))
+    psi = fuse(psi, ghz(2), (1, 2), (2, 1))
+    return relabel(psi, label)
+
+if __name__ == '__main__':
+    print ghz(0).nodes()
+    print ghz(1).nodes()
+    print fuse(ghz(0), ghz(1), (0, 2), (1, 0)).adj
+    print microcluster("pete").nodes()
+
+    g = GraphState()
+    g.from_nx(microcluster("pete"))
+    print g.to_stabilizer()
+