Fix MIP toggle bug: handle PuLP import gracefully

main.py

@@ -14,11 +14,7 @@ from sklearn.cluster import KMeans
 
 from esau_williams import design_with_esau_williams
 from ga import design_with_ga
-
+from mip import design_with_mip
-try:
-    from mip import design_with_mip
-except ImportError:
-    design_with_mip = None
 
 # 设置matplotlib支持中文显示
 plt.rcParams["font.sans-serif"] = ["Microsoft YaHei", "SimHei", "Arial"]
@@ -1715,7 +1711,7 @@ def compare_design_methods(
                 f"  [GA] Cost: ¥{eval_ga['total_cost']:,.2f} | Loss: {eval_ga['total_loss']:.2f} kW | Circuits: {n_circuits_ga}"
             )
 
-        if use_mip and design_with_mip:
+        if use_mip:
             # --- Run 5: Mixed Integer Programming ---
             mip_name = f"{name} (MIP)"
             conns_mip, turbines_mip = design_with_mip(

mip.py

@@ -3,7 +3,12 @@ import pandas as pd
 from scipy.spatial import distance_matrix
 from scipy.sparse.csgraph import minimum_spanning_tree
 from collections import defaultdict
-import pulp
+import random
+
+try:
+    import pulp
+except ImportError:
+    pulp = None
 
 
 def design_with_mip(
@@ -32,13 +37,19 @@ def design_with_mip(
     :param get_max_capacity_func: 获取最大容量函数
     :return: 连接列表和带有簇信息的turbines
     """
+    if pulp is None:
+        print(
+            "WARNING: PuLP library not available. MIP optimization skipped, falling back to MST."
+        )
+        from main import design_with_mst
+
+        return design_with_mst(turbines, substation)
+
     if get_max_capacity_func:
         max_mw = get_max_capacity_func(cable_specs, voltage, power_factor)
     else:
         max_mw = 100.0  # 默认值
-
     total_power = turbines["power"].sum()
-    if max_clusters is None:
     max_clusters = int(np.ceil(total_power / max_mw))
     n_turbines = len(turbines)