adding default case

Signed-off-by: Nicholas Parente <parentenickj@gmail.com>

dowhy/causal_identifier/adjustment_set.py

@@ -23,5 +23,5 @@ def get_variables(self):
         return self.variables
 
     def get_num_paths_blocked_by_observed_nodes(self):
-        """Return the number of paths blocked by the observed nodes (optional)"""
+        """Return the number of paths blocked by observed nodes (optional)"""
         return self.num_paths_blocked_by_observed_nodes

dowhy/causal_identifier/auto_identifier.py

@@ -2,6 +2,7 @@
 import logging
 from enum import Enum
 from typing import Dict, List, Optional, Union
+import copy
 
 import networkx as nx
 import sympy as sp
@@ -21,6 +22,8 @@
     get_descendants,
     get_instruments,
     has_directed_path,
+    get_proper_causal_path_nodes,
+    get_proper_backdoor_graph
 )
 from dowhy.utils.api import parse_state
 
@@ -884,7 +887,24 @@ def identify_complete_adjustment_set(
     observed_nodes: List[str],
     covariate_adjustment: CovariateAdjustment = CovariateAdjustment.COVARIATE_ADJUSTMENT_DEFAULT
 ) -> List[AdjustmentSet]:
-    # TODO: Implement this. Must return a list of AdjustmentSet objects.
+
+    graph_pbd = get_proper_backdoor_graph(graph, action_nodes, outcome_nodes)
+    pcp_nodes = get_proper_causal_path_nodes(graph, action_nodes, outcome_nodes)
+
+    if covariate_adjustment == CovariateAdjustment.COVARIATE_ADJUSTMENT_DEFAULT:
+        # In default case, we don't find all exhaustive adjustment sets
+        adjustment_set = nx.algorithms.find_minimal_d_separator(
+            graph_pbd,
+            action_nodes,
+            outcome_nodes,
+            # Require the adjustment set to consist only of observed nodes
+            restricted=((set(graph.nodes) - set(pcp_nodes)) & set(observed_nodes))
+        )
+        if adjustment_set is None:
+            logger.info("No adjustment sets found.")
+            return []
+        return [AdjustmentSet(AdjustmentSet.GENERAL, adjustment_set)]
+
     return [AdjustmentSet(AdjustmentSet.GENERAL, [])]
 
 

dowhy/graph.py

@@ -5,6 +5,7 @@
 import re
 from abc import abstractmethod
 from typing import Any, List, Protocol
+import copy
 
 import networkx as nx
 from networkx.algorithms.dag import has_cycle
@@ -187,13 +188,53 @@ def is_blocked(graph: nx.DiGraph, path, conditioned_nodes):
         return False
 
 
+def get_ancestors(graph: nx.DiGraph, nodes):
+    ancestors = set()
+    for node_name in nodes:
+        ancestors = ancestors.union(set(nx.ancestors(graph, node_name)))
+    return ancestors
+
+
 def get_descendants(graph: nx.DiGraph, nodes):
     descendants = set()
     for node_name in nodes:
         descendants = descendants.union(set(nx.descendants(graph, node_name)))
     return descendants
 
 
+def get_proper_causal_path_nodes(graph: nx.DiGraph, action_nodes, outcome_nodes):
+    # Process is described in Van Der Zander et al. "Constructing Separators and
+    # Adjustment Sets in Ancestral Graphs", Section 4.1
+
+    # 1) Create modified graphs removing inbound and outbound arrows from the action nodes, respectively.
+    graph_post_interv = copy.deepcopy(graph)  # remove incoming arrows to our action nodes
+    edges_to_remove = [(u, v) for u, v in graph_post_interv.in_edges(action_nodes)]
+    graph_post_interv.remove_edges_from(edges_to_remove)
+    graph_with_action_nodes_as_sinks = copy.deepcopy(graph)  # remove outbound arrows from our action nodes
+    edges_to_remove = [(u, v) for u, v in graph_with_action_nodes_as_sinks.out_edges(action_nodes)]
+    graph_with_action_nodes_as_sinks.remove_edges_from(edges_to_remove)
+
+    # 2) Use the modified graphs to identify the nodes which lie on proper causal paths from the
+    # action nodes to the outcome nodes.
+    de_x = get_descendants(graph_post_interv, action_nodes)
+    an_y = get_ancestors(graph_with_action_nodes_as_sinks, outcome_nodes)
+    return (set(de_x) - set(action_nodes)) & an_y
+
+
+def get_proper_backdoor_graph(graph: nx.DiGraph, action_nodes, outcome_nodes):
+    # Process is described in Van Der Zander et al. "Constructing Separators and
+    # Adjustment Sets in Ancestral Graphs", Section 4.1
+
+    # First we can just call get_proper_causal_path_nodes, then
+    # we remove edges from the action_nodes to the proper causal path nodes
+    graph_pbd = copy.deepcopy(graph)
+    graph_pbd.remove_edges_from(
+        [(u, v) for u in action_nodes for v in get_proper_causal_path_nodes(graph, action_nodes, outcome_nodes)]
+    )
+    return graph_pbd
+
+
+
 def check_dseparation(graph: nx.DiGraph, nodes1, nodes2, nodes3, new_graph=None, dseparation_algo="default"):
     if dseparation_algo == "default":
         if new_graph is None: