def chimera_layout(G, scale=1., center=None, dim=2):
"""Positions the nodes of graph G in a Chimera cross topology.
NumPy (https://scipy.org) is required for this function.
Parameters
----------
G : NetworkX graph
Should be a Chimera graph or a subgraph of a
Chimera graph. If every node in G has a `chimera_index`
attribute, those are used to place the nodes. Otherwise makes
a best-effort attempt to find positions.
scale : float (default 1.)
Scale factor. When scale = 1, all positions fit within [0, 1]
on the x-axis and [-1, 0] on the y-axis.
center : None or array (default None)
Coordinates of the top left corner.
dim : int (default 2)
Number of dimensions. When dim > 2, all extra dimensions are
set to 0.
Returns
-------
pos : dict
A dictionary of positions keyed by node.
Examples
--------
>>> G = dnx.chimera_graph(1)
>>> pos = dnx.chimera_layout(G)
"""
if not isinstance(G, nx.Graph):
empty_graph = nx.Graph()
empty_graph.add_edges_from(G)
G = empty_graph
# now we get chimera coordinates for the translation
# first, check if we made it
if G.graph.get("family") == "chimera":
m = G.graph['rows']
n = G.graph['columns']
t = G.graph['tile']
# get a node placement function
xy_coords = chimera_node_placer_2d(m, n, t, scale, center, dim)
if G.graph.get('labels') == 'coordinate':
pos = {v: xy_coords(*v) for v in G.nodes()}
elif G.graph.get('data'):
pos = {
v: xy_coords(*dat['chimera_index'])
for v, dat in G.nodes(data=True)
}
else:
coord = chimera_coordinates(m, n, t)
pos = {
v: xy_coords(*coord.linear_to_chimera(v))
for v in G.nodes()
}
else:
# best case scenario, each node in G has a chimera_index attribute. Otherwise
# we will try to determine it using the find_chimera_indices function.
if all('chimera_index' in dat for __, dat in G.nodes(data=True)):
chimera_indices = {
v: dat['chimera_index']
for v, dat in G.nodes(data=True)
}
else:
chimera_indices = find_chimera_indices(G)
# we could read these off of the name attribute for G, but we would want the values in
# the nodes to override the name in case of conflict.
m = max(idx[0] for idx in chimera_indices.values()) + 1
n = max(idx[1] for idx in chimera_indices.values()) + 1
t = max(idx[3] for idx in chimera_indices.values()) + 1
xy_coords = chimera_node_placer_2d(m, n, t, scale, center, dim)
# compute our coordinates
pos = {
v: xy_coords(i, j, u, k)
for v, (i, j, u, k) in chimera_indices.items()
}
return pos
def chimera_layout(G, scale=1., center=None, dim=2):
"""Positions the nodes in a Chimera lattice.
NumPy (http://scipy.org) is required for this function.
Parameters
----------
G : graph
A networkx graph. Should be a Chimera graph or a subgraph of a
Chimera graph. If every node in G has a 'chimera_index'
attribute, then those are used to place the nodes. Otherwise will
attempt to find positions, but is not guarunteed to succeed.
scale : float (default 1.)
Scale factor. When scale = 1 the all positions will fit within [0, 1]
on the x-axis and [-1, 0] on the y-axis.
center : None or array (default None)
Coordinates of the top left corner.
dim : int (default 2)
Number of dimensions. When dim > 2, all extra dimensions are
set to 0.
Returns
-------
pos : dict
A dictionary of positions keyed by node.
Examples
--------
>>> G = dnx.chimera_graph(1)
>>> pos = dnx.chimera_layout(G)
"""
if not isinstance(G, nx.Graph):
empty_graph = nx.Graph()
empty_graph.add_nodes_from(G)
G = empty_graph
# best case scenario, each node in G has a chimera_index attribute. Otherwise
# we will try to determine it using the find_chimera_indices function.
if all('chimera_index' in dat for __, dat in G.nodes(data=True)):
chimera_indices = {
v: dat['chimera_index']
for v, dat in G.nodes(data=True)
}
else:
chimera_indices = find_chimera_indices(G)
# we could read these off of the name attribute for G, but we would want the values in
# the nodes to override the name in case of conflict.
m = max(idx[0] for idx in itervalues(chimera_indices)) + 1
n = max(idx[1] for idx in itervalues(chimera_indices)) + 1
t = max(idx[3] for idx in itervalues(chimera_indices)) + 1
# ok, given the chimera indices, let's determine the coordinates
xy_coords = chimera_node_placer_2d(m, n, t, scale, center, dim)
pos = {
v: xy_coords(i, j, u, k)
for v, (i, j, u, k) in iteritems(chimera_indices)
}
return pos
