From 0f93fd0d3851b9c4ba1290d2437debea8941f98c Mon Sep 17 00:00:00 2001
From: Matthias Diener <mdiener@illinois.edu>
Date: Fri, 11 Nov 2022 18:57:03 -0600
Subject: [PATCH] Add validate_graph (#155)
* add validate_graph
* mypy fix
* fix comment
* better exception message
---
pytools/__init__.py | 10 ++++++++--
pytools/graph.py | 25 +++++++++++++++++++++++++
test/test_graph_tools.py | 36 ++++++++++++++++++++++++++++++++++++
3 files changed, 69 insertions(+), 2 deletions(-)
diff --git a/pytools/__init__.py b/pytools/__init__.py
index e018f94..5f1203e 100644
--- a/pytools/__init__.py
+++ b/pytools/__init__.py
@@ -41,9 +41,15 @@ import math
from sys import intern
try:
- from typing import SupportsIndex, ParamSpec, Concatenate
+ from typing import SupportsIndex, Concatenate
except ImportError:
- from typing_extensions import SupportsIndex, ParamSpec, Concatenate
+ from typing_extensions import SupportsIndex, Concatenate
+
+try:
+ from typing import ParamSpec
+except ImportError:
+ from typing_extensions import ParamSpec # type: ignore[assignment]
+
# These are deprecated and will go away in 2022.
all = builtins.all
diff --git a/pytools/graph.py b/pytools/graph.py
index 09c1b41..1eb9147 100644
--- a/pytools/graph.py
+++ b/pytools/graph.py
@@ -37,6 +37,7 @@ Graph Algorithms
.. autofunction:: compute_transitive_closure
.. autofunction:: contains_cycle
.. autofunction:: compute_induced_subgraph
+.. autofunction:: validate_graph
Type Variables Used
-------------------
@@ -394,4 +395,28 @@ def compute_induced_subgraph(graph: Mapping[T, Set[T]],
# }}}
+
+# {{{ validate graph
+
+def validate_graph(graph: Mapping[T, Collection[T]]) -> None:
+ """
+ Validates that all successor nodes of each node in *graph* are keys in
+ *graph* itself. Raises a :class:`ValueError` if not.
+
+ :arg graph: A :class:`collections.abc.Mapping` representing a directed
+ graph. The dictionary contains one key representing each node in the
+ graph, and this key maps to a :class:`collections.abc.Collection` of nodes
+ that are connected to the node by outgoing edges.
+ """
+ seen_nodes: Set[T] = set()
+
+ for children in graph.values():
+ seen_nodes.update(children)
+
+ if not seen_nodes <= graph.keys():
+ raise ValueError(
+ f"invalid graph, missing keys: {seen_nodes-graph.keys()}")
+
+# }}}
+
# vim: foldmethod=marker
diff --git a/test/test_graph_tools.py b/test/test_graph_tools.py
index 5c7a06e..4bb9b8f 100644
--- a/test/test_graph_tools.py
+++ b/test/test_graph_tools.py
@@ -312,6 +312,42 @@ def test_reverse_graph():
assert graph == reverse_graph(reverse_graph(graph))
+def test_validate_graph():
+ from pytools.graph import validate_graph
+ graph1 = {
+ "d": set("c"),
+ "b": set("a"),
+ "a": set(),
+ "c": set("a"),
+ }
+
+ validate_graph(graph1)
+
+ graph2 = {
+ "d": set("d"),
+ "b": set("c"),
+ "a": set("b"),
+ "c": set("a"),
+ }
+
+ validate_graph(graph2)
+
+ graph3 = {
+ "a": {"b", "c"},
+ "b": {"d", "e"},
+ "c": {"d", "f"},
+ "d": set(),
+ "e": set(),
+ "f": {"g"},
+ "g": {"h", "i", "j"}, # h, i, j missing from keys
+ }
+
+ with pytest.raises(ValueError):
+ validate_graph(graph3)
+
+ validate_graph({})
+
+
if __name__ == "__main__":
if len(sys.argv) > 1:
exec(sys.argv[1])
--
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