nx-cugraph: add is_negatively_weighted

python/nx-cugraph/_nx_cugraph/__init__.py

@@ -96,6 +96,7 @@
         "is_connected",
         "is_forest",
         "is_isolate",
+        "is_negatively_weighted",
         "is_tree",
         "is_weakly_connected",
         "isolates",

python/nx-cugraph/nx_cugraph/classes/function.py

@@ -11,11 +11,31 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 import cupy as cp
+import networkx as nx
 
 from nx_cugraph.convert import _to_graph
 from nx_cugraph.utils import networkx_algorithm
 
-__all__ = ["number_of_selfloops"]
+__all__ = [
+    "is_negatively_weighted",
+    "number_of_selfloops",
+]
+
+
+@networkx_algorithm(version_added="24.04")
+def is_negatively_weighted(G, edge=None, weight="weight"):
+    G = _to_graph(G, weight)
+    if edge is not None:
+        data = G.get_edge_data(*edge)
+        if data is None:
+            raise nx.NetworkXError(f"Edge {edge!r} does not exist.")
+        return weight in data and data[weight] < 0
+    if weight not in G.edge_values:
+        return False
+    edge_vals = G.edge_values[weight]
+    if weight in G.edge_masks:
+        edge_vals = edge_vals[G.edge_masks[weight]]
+    return bool((edge_vals < 0).any())
 
 
 @networkx_algorithm(version_added="23.12")

python/nx-cugraph/nx_cugraph/tests/test_classes_function.py

@@ -0,0 +1,35 @@
+# Copyright (c) 2024, NVIDIA CORPORATION.
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Test functions from nx_cugraph/classes/function.py"""
+import networkx as nx
+
+import nx_cugraph as nxcg
+
+
+def test_is_negatively_weighted():
+    Gnx = nx.MultiGraph()
+    Gnx.add_edge(0, 1, 2, weight=-3)
+    Gnx.add_edge(2, 3, foo=3)
+    Gcg = nxcg.from_networkx(Gnx, preserve_edge_attrs=True)
+    assert nx.is_negatively_weighted(Gnx)
+    assert nxcg.is_negatively_weighted(Gnx)
+    assert nxcg.is_negatively_weighted(Gcg)
+    assert not nx.is_negatively_weighted(Gnx, weight="foo")
+    assert not nxcg.is_negatively_weighted(Gcg, weight="foo")
+    assert not nx.is_negatively_weighted(Gnx, weight="bar")
+    assert not nxcg.is_negatively_weighted(Gcg, weight="bar")
+    assert nx.is_negatively_weighted(Gnx, (0, 1, 2))
+    assert nxcg.is_negatively_weighted(Gcg, (0, 1, 2))
+    assert nx.is_negatively_weighted(Gnx, (0, 1)) == nxcg.is_negatively_weighted(
+        Gcg, (0, 1)
+    )

python/nx-cugraph/pyproject.toml

@@ -175,6 +175,7 @@ ignore = [
     # "SIM401",  # Use dict.get ... instead of if-else-block (Note: if-else better for coverage and sometimes clearer)
     # "TRY004",  # Prefer `TypeError` exception for invalid type (Note: good advice, but not worth the nuisance)
     "B904",  # Bare `raise` inside exception clause (like TRY200; sometimes okay)
+    "S310",  # Audit URL open for permitted schemes (Note: we don't download URLs in normal usage)
 
     # Intentionally ignored
     "A003",  # Class attribute ... is shadowing a python builtin
@@ -232,6 +233,7 @@ ignore = [
 "nx_cugraph/**/tests/*py" = ["S101", "S311", "T201", "D103", "D100"]
 "_nx_cugraph/__init__.py" = ["E501"]
 "nx_cugraph/algorithms/**/*py" = ["D205", "D401"]  # Allow flexible docstrings for algorithms
+"scripts/update_readme.py" = ["INP001"]  # Not part of a package
 
 [tool.ruff.lint.flake8-annotations]
 mypy-init-return = true

python/nx-cugraph/scripts/update_readme.py

@@ -70,6 +70,9 @@ def replace_body(text, match, new_body):
         "https://networkx.org/documentation/stable/reference/"
         "algorithms/component.html#weak-connectivity"
     ),
+    "networkx.classes": (
+        "https://networkx.org/documentation/stable/reference/classes/index.html"
+    ),
 }
 
 
@@ -193,9 +196,9 @@ def get_payload_internal(keys):
 
 
 def find_or_download_objs_file(objs_file_dir):
-    """
-    Returns the path to <objs_file_dir>/objects.inv, downloading it from
-    _objs_file_url if it does not already exist.
+    """Return the path to <objs_file_dir>/objects.inv and download it if necessary.
+
+    Download objects.inv from _objs_file_url if it does not already exist.
     """
     objs_file_path = objs_file_dir / "objects.inv"
     if not objs_file_path.exists():