Apply suggestion from @Copilot

Co-authored-by: Copilot <[email protected]>

Author: Nianle-Li

cpp_easygraph/functions/centrality/eigenvector.cpp

@@ -228,22 +228,22 @@ std::vector<double> compute_eigenvector_eigen(
     std::vector<double> result(n);
 
     try {
-        Eigen::SelfAdjointEigenSolver<Eigen::MatrixXd> solver;
+        Eigen::EigenSolver<Eigen::MatrixXd> solver;
 
         if (n < 1000) {
             Eigen::MatrixXd dense_matrix(eigen_matrix);
             solver.compute(dense_matrix);
 
             int max_idx = 0;
-            double max_val = solver.eigenvalues()[0];
+            double max_val = solver.eigenvalues()[0].real();
             for (int i = 1; i < n; i++) {
-                if (solver.eigenvalues()[i] > max_val) {
-                    max_val = solver.eigenvalues()[i];
+                if (solver.eigenvalues()[i].real() > max_val) {
+                    max_val = solver.eigenvalues()[i].real();
                     max_idx = i;
                 }
             }
 
-            Eigen::VectorXd eigen_vec = solver.eigenvectors().col(max_idx);
+            Eigen::VectorXd eigen_vec = solver.eigenvectors().col(max_idx).real();
             for (int i = 0; i < n; i++) {
                 result[i] = eigen_vec(i);
             }