Optimize the eigenvector and closeness algorithms

cpp_easygraph/CMakeLists.txt

@@ -13,32 +13,55 @@ add_subdirectory(pybind11)
 
 option(EASYGRAPH_ENABLE_GPU "EASYGRAPH_ENABLE_GPU" OFF)
 
-if (EASYGRAPH_ENABLE_GPU)
-
-    pybind11_add_module(cpp_easygraph
-        ${SOURCES}
-        $<TARGET_OBJECTS:gpu_easygraph>
-    )
-
-    set_property(TARGET cpp_easygraph PROPERTY CUDA_ARCHITECTURES all)
+# Find OpenMP (optional)
+find_package(OpenMP)
+if(OpenMP_CXX_FOUND)
+    message(STATUS "Found OpenMP: ${OpenMP_CXX_VERSION}")
+else()
+    message(STATUS "OpenMP not found; continuing without OpenMP")
+endif()
 
-    target_compile_definitions(cpp_easygraph 
-        PRIVATE EASYGRAPH_ENABLE_GPU
-    )
+# Find ARPACK (optional; do not fail if absent)
+find_library(ARPACK_LIB NAMES arpack arpack_double)
+if(ARPACK_LIB)
+    message(STATUS "Found ARPACK library: ${ARPACK_LIB}")
+    add_compile_definitions(HAVE_ARPACK=1)
+else()
+    message(WARNING "ARPACK not found; ARPACK-based solvers will be disabled (fallback used).")
+    add_compile_definitions(HAVE_ARPACK=0)
+endif()
 
-    target_link_libraries(cpp_easygraph
-        PRIVATE cudart_static
-    )
+find_package(LAPACK REQUIRED)
 
+# Find Eigen (optional). Change to REQUIRED if Eigen must be enforced.
+find_package(Eigen3 QUIET)
+if(Eigen3_FOUND)
+    message(STATUS "Found Eigen3: ${Eigen3_INCLUDE_DIRS}")
+    add_compile_definitions(HAVE_EIGEN=1)
 else()
+    message(STATUS "Eigen3 not found; eigen-accelerated code will be disabled")
+    add_compile_definitions(HAVE_EIGEN=0)
+endif()
 
-    pybind11_add_module(cpp_easygraph
-        ${SOURCES}
-    )
+# Link/include to cpp_easygraph only if the target exists.
+# This avoids errors when the target is created elsewhere or later.
+if(TARGET cpp_easygraph)
+    if(Eigen3_FOUND)
+        target_include_directories(cpp_easygraph PRIVATE ${Eigen3_INCLUDE_DIRS})
+        if(TARGET Eigen3::Eigen)
+            target_link_libraries(cpp_easygraph PRIVATE Eigen3::Eigen)
+        endif()
+    endif()
 
-endif()
+    if(OpenMP_CXX_FOUND)
+        target_link_libraries(cpp_easygraph PRIVATE OpenMP::OpenMP_CXX)
+    endif()
 
-set_target_properties(cpp_easygraph  PROPERTIES
-    LINK_SEARCH_START_STATIC ON
-    LINK_SEARCH_END_STATIC ON
-)
+    if(ARPACK_LIB)
+        target_link_libraries(cpp_easygraph PRIVATE ${ARPACK_LIB} LAPACK::LAPACK)
+    else()
+        target_link_libraries(cpp_easygraph PRIVATE LAPACK::LAPACK)
+    endif()
+else()
+    message(STATUS "cpp_easygraph target not defined yet; optional libs will be linked after target creation.")
+endif()

cpp_easygraph/cpp_easygraph.cpp

@@ -83,6 +83,7 @@ PYBIND11_MODULE(cpp_easygraph, m) {
     m.def("cpp_constraint", &constraint, py::arg("G"), py::arg("nodes") = py::none(), py::arg("weight") = py::none(), py::arg("n_workers") = py::none());
     m.def("cpp_effective_size", &effective_size, py::arg("G"), py::arg("nodes") = py::none(), py::arg("weight") = py::none(), py::arg("n_workers") = py::none());
     m.def("cpp_efficiency", &efficiency, py::arg("G"), py::arg("nodes") = py::none(), py::arg("weight") = py::none(), py::arg("n_workers") = py::none());
+    m.def("cpp_eigenvector_centrality", &cpp_eigenvector_centrality, py::arg("G"), py::arg("max_iter") = 100, py::arg("tol") = 1.0e-6, py::arg("nstart") = py::none(), py::arg("weight") = py::none());
     m.def("cpp_hierarchy", &hierarchy, py::arg("G"), py::arg("nodes") = py::none(), py::arg("weight") = py::none(), py::arg("n_workers") = py::none());
     m.def("cpp_pagerank", &_pagerank, py::arg("G"), py::arg("alpha") = 0.85, py::arg("max_iterator") = 500, py::arg("threshold") = 1e-6);
     m.def("cpp_dijkstra_multisource", &_dijkstra_multisource, py::arg("G"), py::arg("sources"), py::arg("weight") = "weight", py::arg("target") = py::none());    

cpp_easygraph/functions/centrality/centrality.h

@@ -12,4 +12,11 @@ py::object cpp_katz_centrality(
     py::object py_max_iter,
     py::object py_tol,
     py::object py_normalized
+);
+py::object cpp_eigenvector_centrality(
+    py::object G,
+    py::object py_max_iter,
+    py::object py_tol,
+    py::object py_nstart,
+    py::object py_weight
 );