new: support use_gpu algorithm parameter

Author: aMahanna

README.md

@@ -166,13 +166,16 @@ import nx_arangodb as nxadb
 
 G = nxadb.Graph(name="MyGraph")
 
+# Option 1: Use Global Config
 nx.config.backends.arangodb.use_gpu = False
-
 nx.pagerank(G)
 nx.betweenness_centrality(G)
 # ...
-
 nx.config.backends.arangodb.use_gpu = True
+
+# Option 2: Use Local Config
+nx.pagerank(G, use_gpu=False)
+nx.betweenness_centrality(G, use_gpu=False)
 ```
 
 <p align="center">

doc/algorithms/index.rst

@@ -43,14 +43,17 @@ You can also force-run algorithms on CPU even if ``nx-cugraph`` is installed:
 
    G = nxadb.Graph(name="MyGraph")
 
+   # Option 1: Use Global Config
    nx.config.backends.arangodb.use_gpu = False
-
    nx.pagerank(G)
    nx.betweenness_centrality(G)
    # ...
-
    nx.config.backends.arangodb.use_gpu = True
 
+   # Option 2: Use Local Config
+   nx.pagerank(G, use_gpu=False)
+   nx.betweenness_centrality(G, use_gpu=False)
+
 
 .. image:: ../_static/dispatch.png
    :align: center

doc/nx_arangodb.ipynb

@@ -236,9 +236,7 @@
       "outputs": [],
       "source": [
         "# 5. Run an algorithm (CPU)\n",
-        "nx.config.backends.arangodb.use_gpu = False # Optional\n",
-        "\n",
-        "res = nx.pagerank(G)"
+        "res = nx.pagerank(G, use_gpu=False)"
       ]
     },
     {
@@ -357,8 +355,6 @@
       "source": [
         "# 4. Run an algorithm (GPU)\n",
         "# See *Package Installation* to install nx-cugraph ^\n",
-        "nx.config.backends.arangodb.use_gpu = True\n",
-        "\n",
         "res = nx.pagerank(G)"
       ]
     },

nx_arangodb/interface.py

@@ -63,7 +63,9 @@ def _auto_func(func_name: str, /, *args: Any, **kwargs: Any) -> Any:
     dfunc = _registered_algorithms[func_name]
 
     backend_priority: list[str] = []
-    if nxadb.convert.GPU_AVAILABLE and nx.config.backends.arangodb.use_gpu:
+
+    use_gpu = bool(kwargs.pop("use_gpu", nx.config.backends.arangodb.use_gpu))
+    if nxadb.convert.GPU_AVAILABLE and use_gpu:
         backend_priority.append("cugraph")
 
     for backend in backend_priority:

tests/test.py

@@ -447,7 +447,12 @@ def test_gpu_pagerank(graph_cls: type[nxadb.Graph]) -> None:
     assert gpu_cached_time < gpu_no_cache_time
     assert_pagerank(res_gpu_cached, res_gpu_no_cache, 10)
 
-    # 4. CPU
+    # 4. CPU (with use_gpu=False)
+    start_cpu_force_no_gpu = time.time()
+    res_cpu_force_no_gpu = nx.pagerank(graph, use_gpu=False)
+    cpu_force_no_gpu_time = time.time() - start_cpu_force_no_gpu
+
+    # 5. CPU
     assert graph.nxcg_graph is not None
     graph.clear_nxcg_cache()
     assert graph.nxcg_graph is None
@@ -456,12 +461,14 @@ def test_gpu_pagerank(graph_cls: type[nxadb.Graph]) -> None:
     start_cpu = time.time()
     res_cpu = nx.pagerank(graph)
     cpu_time = time.time() - start_cpu
+    assert_pagerank(res_cpu, res_cpu_force_no_gpu, 10)
 
     assert graph.nxcg_graph is None
-
     m = "GPU execution should be faster than CPU execution"
     assert gpu_time < cpu_time, m
+    assert gpu_time < cpu_force_no_gpu_time, m
     assert gpu_no_cache_time < cpu_time, m
+    assert gpu_no_cache_time < cpu_force_no_gpu_time, m
     assert_pagerank(res_gpu_no_cache, res_cpu, 10)