upd : extracting irreducibles

src/deep_neurographs/densegraph.py

@@ -67,9 +67,7 @@ def init_graphs(self, swc_dir):
             # Construct Graph
             path = os.path.join(swc_dir, f)
             swc_dict = swc_utils.parse_local_swc(path)
-            graph, xyz_to_node = swc_utils.file_to_graph(
-                swc_dict, set_attrs=True, return_dict=True
-            )
+            graph, xyz_to_node = swc_utils.to_graph(swc_dict, set_attrs=True)
 
             # Store
             xyz_to_id = dict(zip_broadcast(swc_dict["xyz"], f))

src/deep_neurographs/graph_utils.py

@@ -5,143 +5,175 @@
 @email: [email protected]
 
 
-Routines for working with graphs.
+Routines that extract the irreducible components of a graph.
 
 """
 
+from copy import deepcopy
+from random import sample
+
 import networkx as nx
+import numpy as np
+
+from deep_neurographs import geometry_utils, swc_utils, utils
+
+
+def get_irreducibles(swc_dict, prune=True, depth=16, smooth=True):
+    """
+    Gets irreducible components of the graph stored in "swc_dict". The
+    irreducible components consist of the leaf and junction nodes along with
+    the edges among this set of nodes.
+
+    Parameters
+    ----------
+    swc_dict : dict
+        Contents of an swc file.
+    prune : True
+        Indication of whether to prune short branches.
+    depth : int
+        Path length that determines whether a branch is short.
+    smooth : bool
+        Indication of whether to smooth each branch.
+
+    Returns
+    -------
+    leafs : set
+        Nodes with degreee 1.
+    junctions : set
+        Nodes with degree > 2.
+    edges : dict
+        Set of edges connecting nodes in leafs and junctions. The keys are
+        pairs of nodes connected by an edge and values are a dictionary of
+        attributes.
+
+    """
+    # Initializations
+    dense_graph = swc_utils.to_graph(swc_dict)
+    if prune:
+        dense_graph = prune_short_branches(dense_graph, depth)
+
+    # Extract irreducibles
+    leafs, junctions = get_irreducible_nodes(dense_graph)
+    source = sample(leafs, 1)[0]
+    root = None
+    edges = dict()
+    nbs = dict()
+    for (i, j) in nx.dfs_edges(dense_graph, source=source):
+        # Check if start of path is valid
+        if root is None:
+            root = i
+            attrs = __init_edge_attrs(swc_dict, i)
+
+        # Visit j
+        attrs = __upd_edge_attrs(swc_dict, attrs, j)
+        if j in leafs or j in junctions:
+            if smooth:
+                swc_dict, edges = __smooth_branch(
+                    swc_dict, attrs, edges, nbs, root, j
+                )
+            else:
+                edges[(root, j)] = attrs
+            nbs = append_value(nbs, root, j)
+            nbs = append_value(nbs, j, root)
+            root = None
+    return leafs, junctions, edges
 
-from deep_neurographs import swc_utils, utils
 
+def get_irreducible_nodes(graph):
+    """
+    Gets irreducible nodes (i.e. leafs and junctions) of a graph.
 
-def extract_irreducible_graph(swc_dict, prune=True, prune_depth=16):
-    graph = swc_utils.to_graph(swc_dict)
-    leafs, junctions = get_irreducibles(graph)
-    irreducible_edges, leafs = extract_irreducible_edges(
-        graph, leafs, junctions, swc_dict, prune=prune, prune_depth=prune_depth
-    )
-    if prune:
-        irreducible_edges, junctions = check_irreducibility(
-            junctions, irreducible_edges
-        )
-    return leafs, junctions, irreducible_edges
+    Parameters
+    ----------
+    graph : networkx.Graph
+        Graph to be searched.
 
+    Returns
+    -------
+    leafs : set
+        Nodes with degreee 1.
+    junctions : set
+        Nodes with degree > 2.
 
-def get_irreducibles(graph):
-    leafs = []
-    junctions = []
+    """
+    leafs = set()
+    junctions = set()
     for i in graph.nodes:
         if graph.degree[i] == 1:
-            leafs.append(i)
+            leafs.add(i)
         elif graph.degree[i] > 2:
-            junctions.append(i)
+            junctions.add(i)
     return leafs, junctions
 
 
-def extract_irreducible_edges(
-    graph, leafs, junctions, swc_dict, prune=True, prune_depth=16
-):
-    root = None
-    irreducible_edges = dict()
-    for (i, j) in nx.dfs_edges(graph, source=leafs[0]):
-        # Check start of path is valid
-        if root is None:
-            root = i
-            edge = _init_edge(swc_dict=swc_dict, node=i)
-            path_length = 0
+def prune_short_branches(graph, depth):
+    remove_nodes = []
+    for leaf in get_leafs(graph):
+        remove_nodes.extend(inspect_branch(graph, leaf, depth))
+    graph.remove_nodes_from(remove_nodes)
+    return graph
 
-        # Add to path
-        edge["radius"].append(swc_dict["radius"][j])
-        edge["xyz"].append(swc_dict["xyz"][j])
-        path_length += 1
 
-        # Check whether to end path
-        if j in leafs or j in junctions:
-            if prune and path_length <= prune_depth:
-                condition1 = j in leafs and root in junctions
-                condition2 = root in leafs and j in junctions
-                if condition1 or condition2:
-                    leafs.remove(j if condition1 else root)
-                else:
-                    irreducible_edges[(root, j)] = edge
-            else:
-                irreducible_edges[(root, j)] = edge
-            root = None
-    return irreducible_edges, leafs
-
-
-def check_irreducibility(junctions, irreducible_edges):
-    graph = nx.Graph()
-    graph.add_edges_from(irreducible_edges.keys())
-    nx.set_edge_attributes(graph, irreducible_edges)
-    for j in junctions:
-        if j not in graph.nodes:
-            junctions.remove(j)
-        elif graph.degree[j] == 2:
-            # Get join edges
-            nbs = list(graph.neighbors(j))
-            edge1 = graph.get_edge_data(j, nbs[0])
-            edge2 = graph.get_edge_data(j, nbs[1])
-            edge = join_edges(edge1, edge2)
-
-            # Update irreducible edges
-            junctions.remove(j)
-            irreducible_edges = utils.remove_key(
-                irreducible_edges, (j, nbs[0])
-            )
-            irreducible_edges = utils.remove_key(
-                irreducible_edges, (j, nbs[1])
-            )
-            irreducible_edges[tuple(nbs)] = edge
+def inspect_branch(graph, leaf, depth):
+    path = [leaf]
+    for (i, j) in nx.dfs_edges(graph, source=leaf, depth_limit=depth):
+        if graph.degree(j) > 2:
+            return path
+        elif graph.degree(j) == 2:
+            path.append(j)
+    return []
+
 
-            graph.remove_edge(j, nbs[0])
-            graph.remove_edge(j, nbs[1])
-            graph.remove_node(j)
-            graph.add_edge(*tuple(nbs), xyz=edge["xyz"], radius=edge["radius"])
-            if graph.degree[nbs[0]] > 2:
-                junctions.append(nbs[0])
+def get_leafs(graph):
+    return [i for i in graph.nodes if graph.degree[i] == 1]
 
-            if graph.degree[nbs[1]] > 2:
-                junctions.append(nbs[1])
 
-    return irreducible_edges, junctions
+def __smooth_branch(swc_dict, attrs, edges, nbs, root, j):
+    attrs["xyz"] = geometry_utils.smooth_branch(np.array(attrs["xyz"]))
+    swc_dict, edges = upd_xyz(swc_dict, attrs, edges, nbs, root, 0)
+    swc_dict, edges = upd_xyz(swc_dict, attrs, edges, nbs, j, -1)
+    edges[(root, j)] = attrs
+    return swc_dict, edges
 
 
-def join_edges(edge1, edge2):
-    # Last point in edge1 must connect to first point in edge2
-    if edge1["xyz"][0] == edge2["xyz"][0]:
-        edge1 = reverse_edge(edge1)
-    elif edge1["xyz"][-1] == edge2["xyz"][-1]:
-        edge2 = reverse_edge(edge2)
-    elif edge1["xyz"][0] == edge2["xyz"][-1]:
-        edge1 = reverse_edge(edge1)
-        edge2 = reverse_edge(edge2)
-    edge = {
-        "xyz": edge1["xyz"] + edge2["xyz"][1:],
-        "radius": edge1["radius"] + edge2["radius"],
-    }
-    return edge
+def upd_xyz(swc_dict, attrs, edges, nbs, i, start_or_end):
+    if i in nbs.keys():
+        for j in nbs[i]:
+            key = (i, j) if (i, j) in edges.keys() else (j, i)
+            edges = upd_branch_endpoint(
+                edges, key, swc_dict["xyz"][i], attrs["xyz"][start_or_end]
+            )
+    swc_dict["xyz"][i] = attrs["xyz"][start_or_end]
+    return swc_dict, edges
 
 
-def reverse_edge(edge):
-    edge["xyz"].reverse()
-    edge["radius"].reverse()
-    return edge
+def append_value(my_dict, key, value):
+    if key in my_dict.keys():
+        my_dict[key].append(value)
+    else:
+        my_dict[key] = [value]
+    return my_dict
 
 
-def _init_edge(swc_dict=None, node=None):
-    edge = {"radius": [], "xyz": []}
-    if node is not None:
-        edge["radius"].append(swc_dict["radius"][node])
-        edge["xyz"].append(swc_dict["xyz"][node])
-    return edge
+def upd_branch_endpoint(edges, key, old_xyz, new_xyz):
+    if all(edges[key]["xyz"][0] == old_xyz):
+        edges[key]["xyz"][0] = new_xyz
+    else:
+        edges[key]["xyz"][-1] = new_xyz
+    return edges
+
+
+# -- attribute utils --
+def __init_edge_attrs(swc_dict, i):
+    return {"radius": [swc_dict["radius"][i]], "xyz": [swc_dict["xyz"][i]]}
+
+
+def __upd_edge_attrs(swc_dict, attrs, i):
+    attrs["radius"].append(swc_dict["radius"][i])
+    attrs["xyz"].append(swc_dict["xyz"][i])
+    return attrs
 
 
 def get_edge_attr(graph, edge, attr):
     edge_data = graph.get_edge_data(*edge)
     return edge_data[attr]
-
-
-def is_leaf(graph, i):
-    nbs = [j for j in graph.neighbors(i)]
-    return True if len(nbs) == 1 else False