Why does Gurobi find same user cuts when calling the callback function in the root node?

Dear,

I am solving an MIP by adding user cuts only in the root node via Gurobi without pre-solving, Gurobi cuts added, and Gurobi heuristics and with a single thread. The settings are as below.

        model.set(GRB_IntParam_Presolve, 0); 
        model.set(GRB_IntParam_Cuts, 0);
        model.set(GRB_IntParam_CutPasses, 0);
        model.set(GRB_DoubleParam_Heuristics, 0.0);
        model.set(GRB_IntParam_Threads, 1);

I got a log file after implementing a small instance and have a few questions about the implementation of Gurobi based on the log file as below.

Root relaxation: objective 8.215223e+01, 1020 iterations, 0.03 seconds

    Nodes    |    Current Node    |     Objective Bounds      |     Work
 Expl Unexpl |  Obj  Depth IntInf | Incumbent    BestBd   Gap | It/Node Time

     0     0   82.15223    0   47          -   82.15223      -     -    0s

This is the 1st time calling the callback.

Solution X  for vehicle type h = 0
x_0,1^0 = -0  x_0,2^0 = 0  x_0,3^0 = 0  x_0,4^0 = -0  x_0,5^0 = 0  x_0,6^0 = 0  x_0,7^0 = -0  x_0,8^0 = -0  x_0,9^0 = 0  x_0,10^0 = -0  x_0,11^0 = -0  x_0,12^0 = 0  x_0,13^0 = 0  x_0,14^0 = 1  x_0,15^0 = -0
x_1,0^0 = 0.190034  x_1,2^0 = -0  x_1,3^0 = -0  x_1,4^0 = -0  x_1,5^0 = -0  x_1,6^0 = -0  x_1,7^0 = -0  x_1,8^0 = -0  x_1,9^0 = -0  x_1,10^0 = -0  x_1,11^0 = -0  x_1,12^0 = -0  x_1,13^0 = 0  x_1,14^0 = -0  x_1,15^0 = -0
x_2,0^0 = -0  x_2,1^0 = -0  x_2,3^0 = -0  x_2,4^0 = -0  x_2,5^0 = -0  x_2,6^0 = -0  x_2,7^0 = -0  x_2,8^0 = -0  x_2,9^0 = 0  x_2,10^0 = 0  x_2,11^0 = 0  x_2,12^0 = -0  x_2,13^0 = 0  x_2,14^0 = -0  x_2,15^0 = 0
x_3,0^0 = -0  x_3,1^0 = -0  x_3,2^0 = -0  x_3,4^0 = 0.054807  x_3,5^0 = -0  x_3,6^0 = -0  x_3,7^0 = -0  x_3,8^0 = -0  x_3,9^0 = -0  x_3,10^0 = -0  x_3,11^0 = -0  x_3,12^0 = -0  x_3,13^0 = -0  x_3,14^0 = -0  x_3,15^0 = -0
x_4,0^0 = 0.185956  x_4,1^0 = -0  x_4,2^0 = -0  x_4,3^0 = 0  x_4,5^0 = -0  x_4,6^0 = -0  x_4,7^0 = -0  x_4,8^0 = -0  x_4,9^0 = -0  x_4,10^0 = -0  x_4,11^0 = -0  x_4,12^0 = -0  x_4,13^0 = 0.517744  x_4,14^0 = -0  x_4,15^0 = -0
x_5,0^0 = -0  x_5,1^0 = 0  x_5,2^0 = -0  x_5,3^0 = -0  x_5,4^0 = 0  x_5,6^0 = 0  x_5,7^0 = 0  x_5,8^0 = -0  x_5,9^0 = -0  x_5,10^0 = 0  x_5,11^0 = -0  x_5,12^0 = -0  x_5,13^0 = 0  x_5,14^0 = -0  x_5,15^0 = -0
x_6,0^0 = -0  x_6,1^0 = -0  x_6,2^0 = -0  x_6,3^0 = -0  x_6,4^0 = 0.648893  x_6,5^0 = -0  x_6,7^0 = 0  x_6,8^0 = 0.106266  x_6,9^0 = 0  x_6,10^0 = 0.190034  x_6,11^0 = 0  x_6,12^0 = 0  x_6,13^0 = -0  x_6,14^0 = 0  x_6,15^0 = -0
x_7,0^0 = -0  x_7,1^0 = -0  x_7,2^0 = -0  x_7,3^0 = -0  x_7,4^0 = -0  x_7,5^0 = -0  x_7,6^0 = 0  x_7,8^0 = 0  x_7,9^0 = -0  x_7,10^0 = -0  x_7,11^0 = 0  x_7,12^0 = -0  x_7,13^0 = 0  x_7,14^0 = -0  x_7,15^0 = -0
x_8,0^0 = 0.106266  x_8,1^0 = -0  x_8,2^0 = -0  x_8,3^0 = -0  x_8,4^0 = 0  x_8,5^0 = -0  x_8,6^0 = -0  x_8,7^0 = -0  x_8,9^0 = -0  x_8,10^0 = -0  x_8,11^0 = -0  x_8,12^0 = -0  x_8,13^0 = -0  x_8,14^0 = -0  x_8,15^0 = -0
x_9,0^0 = 0  x_9,1^0 = -0  x_9,2^0 = -0  x_9,3^0 = -0  x_9,4^0 = 0  x_9,5^0 = -0  x_9,6^0 = -0  x_9,7^0 = -0  x_9,8^0 = -0  x_9,10^0 = -0  x_9,11^0 = -0  x_9,12^0 = -0  x_9,13^0 = 0  x_9,14^0 = -0  x_9,15^0 = -0
x_10,0^0 = -0  x_10,1^0 = 0.190034  x_10,2^0 = -0  x_10,3^0 = -0  x_10,4^0 = -0  x_10,5^0 = -0  x_10,6^0 = -0  x_10,7^0 = -0  x_10,8^0 = -0  x_10,9^0 = -0  x_10,11^0 = -0  x_10,12^0 = -0  x_10,13^0 = 0  x_10,14^0 = -0  x_10,15^0 = -0
x_11,0^0 = 0  x_11,1^0 = -0  x_11,2^0 = -0  x_11,3^0 = -0  x_11,4^0 = -0  x_11,5^0 = -0  x_11,6^0 = -0  x_11,7^0 = -0  x_11,8^0 = -0  x_11,9^0 = -0  x_11,10^0 = -0  x_11,12^0 = -0  x_11,13^0 = -0  x_11,14^0 = -0  x_11,15^0 = -0
x_12,0^0 = 0  x_12,1^0 = 0  x_12,2^0 = -0  x_12,3^0 = -0  x_12,4^0 = -0  x_12,5^0 = -0  x_12,6^0 = -0  x_12,7^0 = 0  x_12,8^0 = 0  x_12,9^0 = -0  x_12,10^0 = -0  x_12,11^0 = -0  x_12,13^0 = 0  x_12,14^0 = -0  x_12,15^0 = -0
x_13,0^0 = 0.517744  x_13,1^0 = -0  x_13,2^0 = -0  x_13,3^0 = -0  x_13,4^0 = 0  x_13,5^0 = -0  x_13,6^0 = -0  x_13,7^0 = -0  x_13,8^0 = -0  x_13,9^0 = -0  x_13,10^0 = -0  x_13,11^0 = -0  x_13,12^0 = -0  x_13,14^0 = -0  x_13,15^0 = -0
x_14,0^0 = -0  x_14,1^0 = -0  x_14,2^0 = -0  x_14,3^0 = 0  x_14,4^0 = -0  x_14,5^0 = -0  x_14,6^0 = -0  x_14,7^0 = -0  x_14,8^0 = 0  x_14,9^0 = -0  x_14,10^0 = 0  x_14,11^0 = -0  x_14,12^0 = -0  x_14,13^0 = 0  x_14,15^0 = 1
x_15,0^0 = -0  x_15,1^0 = 0  x_15,2^0 = -0  x_15,3^0 = 0.054807  x_15,4^0 = -0  x_15,5^0 = -0  x_15,6^0 = 0.945193  x_15,7^0 = 0  x_15,8^0 = 0  x_15,9^0 = -0  x_15,10^0 = -0  x_15,11^0 = -0  x_15,12^0 = -0  x_15,13^0 = 0  x_15,14^0 = -0

Solution X  for vehicle type h = 1
x_0,1^1 = -0  x_0,2^1 = 1  x_0,3^1 = -0  x_0,4^1 = -0  x_0,5^1 = 1  x_0,6^1 = -0  x_0,7^1 = -0  x_0,8^1 = -0  x_0,9^1 = -0  x_0,10^1 = -0  x_0,11^1 = -0  x_0,12^1 = 0  x_0,13^1 = -0  x_0,14^1 = -0  x_0,15^1 = -0
x_1,0^1 = 0.809966  x_1,2^1 = -0  x_1,3^1 = -0  x_1,4^1 = -0  x_1,5^1 = -0  x_1,6^1 = 0  x_1,7^1 = 0  x_1,8^1 = -0  x_1,9^1 = -0  x_1,10^1 = 0  x_1,11^1 = -0  x_1,12^1 = -0  x_1,13^1 = -0  x_1,14^1 = -0  x_1,15^1 = -0
x_2,0^1 = -0  x_2,1^1 = -0  x_2,3^1 = -0  x_2,4^1 = -0  x_2,5^1 = 0  x_2,6^1 = -0  x_2,7^1 = 0  x_2,8^1 = -0  x_2,9^1 = -0  x_2,10^1 = -0  x_2,11^1 = -0  x_2,12^1 = 1  x_2,13^1 = -0  x_2,14^1 = 0  x_2,15^1 = -0
x_3,0^1 = 0.0489293  x_3,1^1 = -0  x_3,2^1 = 0  x_3,4^1 = 0.2963  x_3,5^1 = 0  x_3,6^1 = -0  x_3,7^1 = 0  x_3,8^1 = 0  x_3,9^1 = 0.117708  x_3,10^1 = -0  x_3,11^1 = 0  x_3,12^1 = 0  x_3,13^1 = 0.482256  x_3,14^1 = 0  x_3,15^1 = 0
x_4,0^1 = 0.2963  x_4,1^1 = 0  x_4,2^1 = 0  x_4,3^1 = -0  x_4,5^1 = 0  x_4,6^1 = 0  x_4,7^1 = 0  x_4,8^1 = -0  x_4,9^1 = -0  x_4,10^1 = -0  x_4,11^1 = -0  x_4,12^1 = 0  x_4,13^1 = -0  x_4,14^1 = -0  x_4,15^1 = 0
x_5,0^1 = -0  x_5,1^1 = -0  x_5,2^1 = 0  x_5,3^1 = -0  x_5,4^1 = -0  x_5,6^1 = -0  x_5,7^1 = -0  x_5,8^1 = -0  x_5,9^1 = -0  x_5,10^1 = -0  x_5,11^1 = 1  x_5,12^1 = 0  x_5,13^1 = -0  x_5,14^1 = 0  x_5,15^1 = 0
x_6,0^1 = -0  x_6,1^1 = -0  x_6,2^1 = -0  x_6,3^1 = -0  x_6,4^1 = -0  x_6,5^1 = 0  x_6,7^1 = -0  x_6,8^1 = 0.0105279  x_6,9^1 = -0  x_6,10^1 = 0.0442791  x_6,11^1 = -0  x_6,12^1 = -0  x_6,13^1 = -0  x_6,14^1 = -0  x_6,15^1 = 0
x_7,0^1 = 0.116794  x_7,1^1 = -0  x_7,2^1 = -0  x_7,3^1 = -0  x_7,4^1 = -0  x_7,5^1 = 0  x_7,6^1 = -0  x_7,8^1 = 0.883206  x_7,9^1 = 0  x_7,10^1 = -0  x_7,11^1 = -0  x_7,12^1 = 0  x_7,13^1 = -0  x_7,14^1 = 0  x_7,15^1 = -0
x_8,0^1 = -0  x_8,1^1 = -0  x_8,2^1 = 0  x_8,3^1 = 0  x_8,4^1 = -0  x_8,5^1 = 0  x_8,6^1 = 0.054807  x_8,7^1 = 0.0732397  x_8,9^1 = 0  x_8,10^1 = 0.765687  x_8,11^1 = 0  x_8,12^1 = -0  x_8,13^1 = -0  x_8,14^1 = 0  x_8,15^1 = 0
x_9,0^1 = 0.054807  x_9,1^1 = -0  x_9,2^1 = 0  x_9,3^1 = 0.945193  x_9,4^1 = -0  x_9,5^1 = 0  x_9,6^1 = 0  x_9,7^1 = 0  x_9,8^1 = 0  x_9,10^1 = 0  x_9,11^1 = 0  x_9,12^1 = 0  x_9,13^1 = -0  x_9,14^1 = 0  x_9,15^1 = 0
x_10,0^1 = -0  x_10,1^1 = 0.809966  x_10,2^1 = 0  x_10,3^1 = -0  x_10,4^1 = 0  x_10,5^1 = 0  x_10,6^1 = 0  x_10,7^1 = 0  x_10,8^1 = 0  x_10,9^1 = 0  x_10,11^1 = 0  x_10,12^1 = -0  x_10,13^1 = -0  x_10,14^1 = 0  x_10,15^1 = 0
x_11,0^1 = 0.0732397  x_11,1^1 = -0  x_11,2^1 = 0  x_11,3^1 = -0  x_11,4^1 = 0  x_11,5^1 = 0  x_11,6^1 = 0  x_11,7^1 = 0.92676  x_11,8^1 = -0  x_11,9^1 = 0  x_11,10^1 = -0  x_11,12^1 = 0  x_11,13^1 = 0  x_11,14^1 = -0  x_11,15^1 = 0
x_12,0^1 = 0.117708  x_12,1^1 = -0  x_12,2^1 = 0  x_12,3^1 = -0  x_12,4^1 = -0  x_12,5^1 = -0  x_12,6^1 = -0  x_12,7^1 = -0  x_12,8^1 = -0  x_12,9^1 = 0.882292  x_12,10^1 = -0  x_12,11^1 = 0  x_12,13^1 = -0  x_12,14^1 = -0  x_12,15^1 = -0
x_13,0^1 = 0.482256  x_13,1^1 = -0  x_13,2^1 = 0  x_13,3^1 = -0  x_13,4^1 = -0  x_13,5^1 = 0  x_13,6^1 = 0  x_13,7^1 = 0  x_13,8^1 = 0  x_13,9^1 = -0  x_13,10^1 = -0  x_13,11^1 = -0  x_13,12^1 = 0  x_13,14^1 = 0  x_13,15^1 = 0
x_14,0^1 = -0  x_14,1^1 = -0  x_14,2^1 = -0  x_14,3^1 = -0  x_14,4^1 = -0  x_14,5^1 = 0  x_14,6^1 = -0  x_14,7^1 = 0  x_14,8^1 = -0  x_14,9^1 = 0  x_14,10^1 = -0  x_14,11^1 = 0  x_14,12^1 = -0  x_14,13^1 = -0  x_14,15^1 = 0
x_15,0^1 = -0  x_15,1^1 = -0  x_15,2^1 = 0  x_15,3^1 = -0  x_15,4^1 = -0  x_15,5^1 = 0  x_15,6^1 = 0  x_15,7^1 = -0  x_15,8^1 = -0  x_15,9^1 = 0  x_15,10^1 = -0  x_15,11^1 = 0  x_15,12^1 = 0  x_15,13^1 = -0  x_15,14^1 = 0


Solution Y for vehicle type h = 0
y_0^0=1  y_1^0=0.190034  y_2^0=0  y_3^0=0.054807  y_4^0=0.7037  y_5^0=0  y_6^0=0.945193  y_7^0=0  y_8^0=0.106266  y_9^0=0  y_10^0=0.190034  y_11^0=0  y_12^0=0  y_13^0=0.517744  y_14^0=1  y_15^0=1

Solution Y for vehicle type h = 1
y_0^1=1  y_1^1=0.809966  y_2^1=1  y_3^1=0.945193  y_4^1=0.2963  y_5^1=1  y_6^1=0.054807  y_7^1=1  y_8^1=0.893734  y_9^1=1  y_10^1=0.809966  y_11^1=1  y_12^1=1  y_13^1=0.482256  y_14^1=0  y_15^1=0

For the vehicle type: 0

 ----- Min s-t cut -----

For the vehicle type: 1

 ----- Min s-t cut -----
=> A min s-t cut, No. 1
+ x_{3,0}^1+ x_{3,1}^1+ x_{3,2}^1+ x_{3,4}^1+ x_{3,5}^1+ x_{3,6}^1+ x_{3,7}^1+ x_{3,8}^1+ x_{3,10}^1+ x_{3,11}^1+ x_{3,12}^1+ x_{3,13}^1+ x_{3,14}^1+ x_{3,15}^1+ x_{9,0}^1+ x_{9,1}^1+ x_{9,2}^1+ x_{9,4}^1+ x_{9,5}^1+ x_{9,6}^1+ x_{9,7}^1+ x_{9,8}^1+ x_{9,10}^1+ x_{9,11}^1+ x_{9,12}^1+ x_{9,13}^1+ x_{9,14}^1+ x_{9,15}^1 >= y_3^1

=> A min s-t cut, No. 2
+ x_{3,0}^1+ x_{3,1}^1+ x_{3,2}^1+ x_{3,4}^1+ x_{3,5}^1+ x_{3,6}^1+ x_{3,7}^1+ x_{3,8}^1+ x_{3,10}^1+ x_{3,11}^1+ x_{3,12}^1+ x_{3,13}^1+ x_{3,14}^1+ x_{3,15}^1+ x_{9,0}^1+ x_{9,1}^1+ x_{9,2}^1+ x_{9,4}^1+ x_{9,5}^1+ x_{9,6}^1+ x_{9,7}^1+ x_{9,8}^1+ x_{9,10}^1+ x_{9,11}^1+ x_{9,12}^1+ x_{9,13}^1+ x_{9,14}^1+ x_{9,15}^1 >= y_9^1

=> A min s-t cut, No. 3
+ x_{6,0}^1+ x_{6,1}^1+ x_{6,2}^1+ x_{6,3}^1+ x_{6,4}^1+ x_{6,5}^1+ x_{6,9}^1+ x_{6,10}^1+ x_{6,11}^1+ x_{6,12}^1+ x_{6,13}^1+ x_{6,14}^1+ x_{6,15}^1+ x_{7,0}^1+ x_{7,1}^1+ x_{7,2}^1+ x_{7,3}^1+ x_{7,4}^1+ x_{7,5}^1+ x_{7,9}^1+ x_{7,10}^1+ x_{7,11}^1+ x_{7,12}^1+ x_{7,13}^1+ x_{7,14}^1+ x_{7,15}^1+ x_{8,0}^1+ x_{8,1}^1+ x_{8,2}^1+ x_{8,3}^1+ x_{8,4}^1+ x_{8,5}^1+ x_{8,9}^1+ x_{8,10}^1+ x_{8,11}^1+ x_{8,12}^1+ x_{8,13}^1+ x_{8,14}^1+ x_{8,15}^1 >= y_7^1

=> A min s-t cut, No. 4
+ x_{6,0}^1+ x_{6,1}^1+ x_{6,2}^1+ x_{6,3}^1+ x_{6,4}^1+ x_{6,5}^1+ x_{6,7}^1+ x_{6,9}^1+ x_{6,10}^1+ x_{6,11}^1+ x_{6,12}^1+ x_{6,13}^1+ x_{6,14}^1+ x_{6,15}^1+ x_{8,0}^1+ x_{8,1}^1+ x_{8,2}^1+ x_{8,3}^1+ x_{8,4}^1+ x_{8,5}^1+ x_{8,7}^1+ x_{8,9}^1+ x_{8,10}^1+ x_{8,11}^1+ x_{8,12}^1+ x_{8,13}^1+ x_{8,14}^1+ x_{8,15}^1 >= y_8^1

=> A min s-t cut, No. 5
+ x_{3,0}^1+ x_{3,1}^1+ x_{3,2}^1+ x_{3,4}^1+ x_{3,5}^1+ x_{3,6}^1+ x_{3,7}^1+ x_{3,8}^1+ x_{3,10}^1+ x_{3,11}^1+ x_{3,12}^1+ x_{3,13}^1+ x_{3,14}^1+ x_{3,15}^1+ x_{9,0}^1+ x_{9,1}^1+ x_{9,2}^1+ x_{9,4}^1+ x_{9,5}^1+ x_{9,6}^1+ x_{9,7}^1+ x_{9,8}^1+ x_{9,10}^1+ x_{9,11}^1+ x_{9,12}^1+ x_{9,13}^1+ x_{9,14}^1+ x_{9,15}^1 >= y_3^1

=> A min s-t cut, No. 6
+ x_{3,0}^1+ x_{3,1}^1+ x_{3,2}^1+ x_{3,4}^1+ x_{3,5}^1+ x_{3,6}^1+ x_{3,7}^1+ x_{3,8}^1+ x_{3,10}^1+ x_{3,11}^1+ x_{3,12}^1+ x_{3,13}^1+ x_{3,14}^1+ x_{3,15}^1+ x_{9,0}^1+ x_{9,1}^1+ x_{9,2}^1+ x_{9,4}^1+ x_{9,5}^1+ x_{9,6}^1+ x_{9,7}^1+ x_{9,8}^1+ x_{9,10}^1+ x_{9,11}^1+ x_{9,12}^1+ x_{9,13}^1+ x_{9,14}^1+ x_{9,15}^1 >= y_9^1

Root_bestbound = 82.1522

This is the 2nd time calling the callback.

Solution X  for vehicle type h = 0
x_0,1^0 = -0  x_0,2^0 = 0.0276109  x_0,3^0 = 0  x_0,4^0 = -0  x_0,5^0 = 0.0746472  x_0,6^0 = 0  x_0,7^0 = -0  x_0,8^0 = -0  x_0,9^0 = 0  x_0,10^0 = -0  x_0,11^0 = -0  x_0,12^0 = 0.0971179  x_0,13^0 = 0  x_0,14^0 = 0.800624  x_0,15^0 = -0
x_1,0^0 = 0.117063  x_1,2^0 = -0  x_1,3^0 = -0  x_1,4^0 = -0  x_1,5^0 = -0  x_1,6^0 = -0  x_1,7^0 = -0  x_1,8^0 = -0  x_1,9^0 = -0  x_1,10^0 = -0  x_1,11^0 = -0  x_1,12^0 = -0  x_1,13^0 = 0  x_1,14^0 = -0  x_1,15^0 = -0
x_2,0^0 = 0.0175069  x_2,1^0 = -0  x_2,3^0 = -0  x_2,4^0 = -0  x_2,5^0 = -0  x_2,6^0 = -0  x_2,7^0 = 0  x_2,8^0 = -0  x_2,9^0 = 0.010104  x_2,10^0 = 0  x_2,11^0 = 0  x_2,12^0 = -0  x_2,13^0 = 0  x_2,14^0 = -0  x_2,15^0 = 0
x_3,0^0 = -0  x_3,1^0 = -0  x_3,2^0 = -0  x_3,4^0 = -0  x_3,5^0 = -0  x_3,6^0 = -0  x_3,7^0 = -0  x_3,8^0 = -0  x_3,9^0 = -0  x_3,10^0 = -0  x_3,11^0 = -0  x_3,12^0 = -0  x_3,13^0 = -0  x_3,14^0 = -0  x_3,15^0 = -0
x_4,0^0 = 0.09311  x_4,1^0 = -0  x_4,2^0 = -0  x_4,3^0 = -0  x_4,5^0 = -0  x_4,6^0 = -0  x_4,7^0 = -0  x_4,8^0 = -0  x_4,9^0 = -0  x_4,10^0 = -0  x_4,11^0 = -0  x_4,12^0 = -0  x_4,13^0 = 0.484119  x_4,14^0 = -0  x_4,15^0 = -0
x_5,0^0 = -0  x_5,1^0 = 0  x_5,2^0 = -0  x_5,3^0 = -0  x_5,4^0 = 0  x_5,6^0 = 0  x_5,7^0 = -0  x_5,8^0 = -0  x_5,9^0 = 0  x_5,10^0 = 0  x_5,11^0 = 0.0746472  x_5,12^0 = -0  x_5,13^0 = 0  x_5,14^0 = -0  x_5,15^0 = -0
x_6,0^0 = -0  x_6,1^0 = -0  x_6,2^0 = -0  x_6,3^0 = -0  x_6,4^0 = 0.577229  x_6,5^0 = -0  x_6,7^0 = 0  x_6,8^0 = 0.106332  x_6,9^0 = 0  x_6,10^0 = 0.117063  x_6,11^0 = 0  x_6,12^0 = 0  x_6,13^0 = -0  x_6,14^0 = 0  x_6,15^0 = -0
x_7,0^0 = -0  x_7,1^0 = -0  x_7,2^0 = -0  x_7,3^0 = -0  x_7,4^0 = -0  x_7,5^0 = -0  x_7,6^0 = 0  x_7,8^0 = 0  x_7,9^0 = -0  x_7,10^0 = -0  x_7,11^0 = 0  x_7,12^0 = -0  x_7,13^0 = 0  x_7,14^0 = -0  x_7,15^0 = -0
x_8,0^0 = 0.106332  x_8,1^0 = -0  x_8,2^0 = -0  x_8,3^0 = -0  x_8,4^0 = 0  x_8,5^0 = -0  x_8,6^0 = -0  x_8,7^0 = -0  x_8,9^0 = -0  x_8,10^0 = -0  x_8,11^0 = -0  x_8,12^0 = -0  x_8,13^0 = -0  x_8,14^0 = -0  x_8,15^0 = -0
x_9,0^0 = 0.010104  x_9,1^0 = -0  x_9,2^0 = -0  x_9,3^0 = 0  x_9,4^0 = 0  x_9,5^0 = -0  x_9,6^0 = -0  x_9,7^0 = -0  x_9,8^0 = -0  x_9,10^0 = -0  x_9,11^0 = -0  x_9,12^0 = -0  x_9,13^0 = 0  x_9,14^0 = -0  x_9,15^0 = -0
x_10,0^0 = -0  x_10,1^0 = 0.117063  x_10,2^0 = -0  x_10,3^0 = -0  x_10,4^0 = -0  x_10,5^0 = -0  x_10,6^0 = -0  x_10,7^0 = -0  x_10,8^0 = -0  x_10,9^0 = -0  x_10,11^0 = -0  x_10,12^0 = -0  x_10,13^0 = 0  x_10,14^0 = -0  x_10,15^0 = -0
x_11,0^0 = 0.0746472  x_11,1^0 = -0  x_11,2^0 = -0  x_11,3^0 = -0  x_11,4^0 = -0  x_11,5^0 = -0  x_11,6^0 = -0  x_11,7^0 = -0  x_11,8^0 = -0  x_11,9^0 = -0  x_11,10^0 = -0  x_11,12^0 = -0  x_11,13^0 = -0  x_11,14^0 = -0  x_11,15^0 = -0
x_12,0^0 = 0.0971179  x_12,1^0 = 0  x_12,2^0 = -0  x_12,3^0 = -0  x_12,4^0 = -0  x_12,5^0 = -0  x_12,6^0 = -0  x_12,7^0 = 0  x_12,8^0 = 0  x_12,9^0 = -0  x_12,10^0 = -0  x_12,11^0 = -0  x_12,13^0 = 0  x_12,14^0 = -0  x_12,15^0 = -0
x_13,0^0 = 0.484119  x_13,1^0 = -0  x_13,2^0 = -0  x_13,3^0 = -0  x_13,4^0 = 0  x_13,5^0 = -0  x_13,6^0 = -0  x_13,7^0 = -0  x_13,8^0 = -0  x_13,9^0 = -0  x_13,10^0 = -0  x_13,11^0 = -0  x_13,12^0 = -0  x_13,14^0 = -0  x_13,15^0 = -0
x_14,0^0 = -0  x_14,1^0 = -0  x_14,2^0 = -0  x_14,3^0 = -0  x_14,4^0 = -0  x_14,5^0 = -0  x_14,6^0 = -0  x_14,7^0 = -0  x_14,8^0 = 0  x_14,9^0 = -0  x_14,10^0 = 0  x_14,11^0 = -0  x_14,12^0 = -0  x_14,13^0 = 0  x_14,15^0 = 0.800624
x_15,0^0 = -0  x_15,1^0 = 0  x_15,2^0 = -0  x_15,3^0 = -0  x_15,4^0 = -0  x_15,5^0 = -0  x_15,6^0 = 0.800624  x_15,7^0 = 0  x_15,8^0 = 0  x_15,9^0 = -0  x_15,10^0 = -0  x_15,11^0 = -0  x_15,12^0 = -0  x_15,13^0 = 0  x_15,14^0 = -0

Solution X  for vehicle type h = 1
x_0,1^1 = -0  x_0,2^1 = 0.896434  x_0,3^1 = -0  x_0,4^1 = -0  x_0,5^1 = 0.925353  x_0,6^1 = -0  x_0,7^1 = -0  x_0,8^1 = -0  x_0,9^1 = -0  x_0,10^1 = -0  x_0,11^1 = -0  x_0,12^1 = 0.0175069  x_0,13^1 = -0  x_0,14^1 = 0.160706  x_0,15^1 = -0 
x_1,0^1 = 0.882937  x_1,2^1 = -0  x_1,3^1 = -0  x_1,4^1 = -0  x_1,5^1 = -0  x_1,6^1 = 0  x_1,7^1 = 0  x_1,8^1 = -0  x_1,9^1 = -0  x_1,10^1 = 0  x_1,11^1 = -0  x_1,12^1 = -0  x_1,13^1 = -0  x_1,14^1 = -0  x_1,15^1 = -0
x_2,0^1 = -0  x_2,1^1 = -0  x_2,3^1 = -0  x_2,4^1 = -0  x_2,5^1 = 0  x_2,6^1 = -0  x_2,7^1 = -0  x_2,8^1 = -0  x_2,9^1 = 0.0870139  x_2,10^1 = -0  x_2,11^1 = -0  x_2,12^1 = 0.885375  x_2,13^1 = -0  x_2,14^1 = -0  x_2,15^1 = -0
x_3,0^1 = 0.0512434  x_3,1^1 = -0  x_3,2^1 = 0  x_3,4^1 = 0.422771  x_3,5^1 = 0  x_3,6^1 = -0  x_3,7^1 = 0  x_3,8^1 = 0  x_3,9^1 = 0.010104  x_3,10^1 = -0  x_3,11^1 = 0  x_3,12^1 = 0  x_3,13^1 = 0.515881  x_3,14^1 = 0  x_3,15^1 = 0
x_4,0^1 = 0.422771  x_4,1^1 = 0  x_4,2^1 = 0  x_4,3^1 = 0  x_4,5^1 = 0  x_4,6^1 = 0  x_4,7^1 = 0  x_4,8^1 = -0  x_4,9^1 = -0  x_4,10^1 = -0  x_4,11^1 = -0  x_4,12^1 = 0  x_4,13^1 = -0  x_4,14^1 = -0  x_4,15^1 = 0
x_5,0^1 = -0  x_5,1^1 = -0  x_5,2^1 = 0  x_5,3^1 = -0  x_5,4^1 = -0  x_5,6^1 = -0  x_5,7^1 = -0  x_5,8^1 = -0  x_5,9^1 = -0  x_5,10^1 = -0  x_5,11^1 = 0.925353  x_5,12^1 = 0  x_5,13^1 = -0  x_5,14^1 = 0  x_5,15^1 = 0
x_6,0^1 = -0  x_6,1^1 = -0  x_6,2^1 = -0  x_6,3^1 = -0  x_6,4^1 = -0  x_6,5^1 = 0  x_6,7^1 = -0  x_6,8^1 = 0.0107304  x_6,9^1 = -0  x_6,10^1 = 0.188646  x_6,11^1 = -0  x_6,12^1 = -0  x_6,13^1 = -0  x_6,14^1 = -0  x_6,15^1 = 0
x_7,0^1 = 0.117063  x_7,1^1 = -0  x_7,2^1 = -0  x_7,3^1 = -0  x_7,4^1 = -0  x_7,5^1 = 0  x_7,6^1 = -0  x_7,8^1 = 0.882937  x_7,9^1 = 0  x_7,10^1 = -0  x_7,11^1 = -0  x_7,12^1 = 0  x_7,13^1 = -0  x_7,14^1 = 0  x_7,15^1 = -0
x_8,0^1 = -0  x_8,1^1 = -0  x_8,2^1 = 0  x_8,3^1 = 0  x_8,4^1 = -0  x_8,5^1 = 0  x_8,6^1 = 0.124729  x_8,7^1 = 0.0746472  x_8,9^1 = 0  x_8,10^1 = 0.694292  x_8,11^1 = 0  x_8,12^1 = -0  x_8,13^1 = -0  x_8,14^1 = 0  x_8,15^1 = 0
x_9,0^1 = -0  x_9,1^1 = -0  x_9,2^1 = 0  x_9,3^1 = 0.989896  x_9,4^1 = -0  x_9,5^1 = 0  x_9,6^1 = 0  x_9,7^1 = 0  x_9,8^1 = 0  x_9,10^1 = 0  x_9,11^1 = 0  x_9,12^1 = 0  x_9,13^1 = -0  x_9,14^1 = 0  x_9,15^1 = 0
x_10,0^1 = -0  x_10,1^1 = 0.882937  x_10,2^1 = 0  x_10,3^1 = -0  x_10,4^1 = 0  x_10,5^1 = 0  x_10,6^1 = 0  x_10,7^1 = 0  x_10,8^1 = 0  x_10,9^1 = 0  x_10,11^1 = 0  x_10,12^1 = -0  x_10,13^1 = -0  x_10,14^1 = 0  x_10,15^1 = 0
x_11,0^1 = -0  x_11,1^1 = -0  x_11,2^1 = 0  x_11,3^1 = -0  x_11,4^1 = 0  x_11,5^1 = 0  x_11,6^1 = 0  x_11,7^1 = 0.925353  x_11,8^1 = -0  x_11,9^1 = 0  x_11,10^1 = -0  x_11,12^1 = 0  x_11,13^1 = 0  x_11,14^1 = -0  x_11,15^1 = 0
x_12,0^1 = 0.010104  x_12,1^1 = -0  x_12,2^1 = 0  x_12,3^1 = -0  x_12,4^1 = -0  x_12,5^1 = -0  x_12,6^1 = -0  x_12,7^1 = -0  x_12,8^1 = -0  x_12,9^1 = 0.892778  x_12,10^1 = -0  x_12,11^1 = 0  x_12,13^1 = -0  x_12,14^1 = -0  x_12,15^1 = -0
x_13,0^1 = 0.515881  x_13,1^1 = -0  x_13,2^1 = 0  x_13,3^1 = -0  x_13,4^1 = -0  x_13,5^1 = 0  x_13,6^1 = 0  x_13,7^1 = 0  x_13,8^1 = 0  x_13,9^1 = -0  x_13,10^1 = -0  x_13,11^1 = -0  x_13,12^1 = 0  x_13,14^1 = 0  x_13,15^1 = 0
x_14,0^1 = -0  x_14,1^1 = -0  x_14,2^1 = -0  x_14,3^1 = 0  x_14,4^1 = -0  x_14,5^1 = 0  x_14,6^1 = -0  x_14,7^1 = -0  x_14,8^1 = -0  x_14,9^1 = 0  x_14,10^1 = -0  x_14,11^1 = 0  x_14,12^1 = -0  x_14,13^1 = -0  x_14,15^1 = 0.199376
x_15,0^1 = -0  x_15,1^1 = -0  x_15,2^1 = 0.075955  x_15,3^1 = 0.010104  x_15,4^1 = -0  x_15,5^1 = 0  x_15,6^1 = 0.0746472  x_15,7^1 = -0  x_15,8^1 = -0  x_15,9^1 = 0  x_15,10^1 = -0  x_15,11^1 = 0  x_15,12^1 = 0  x_15,13^1 = -0  x_15,14^1 = 0.0386698


Solution Y for vehicle type h = 0
y_0^0=1  y_1^0=0.117063  y_2^0=0.0276109  y_3^0=0  y_4^0=0.577229  y_5^0=0.0746472  y_6^0=0.800624  y_7^0=0  y_8^0=0.106332  y_9^0=0.010104  y_10^0=0.117063  y_11^0=0.0746472  y_12^0=0.0971179  y_13^0=0.484119  y_14^0=0.800624  y_15^0=0.800624

Solution Y for vehicle type h = 1
y_0^1=1  y_1^1=0.882937  y_2^1=0.972389  y_3^1=1  y_4^1=0.422771  y_5^1=0.925353  y_6^1=0.199376  y_7^1=1  y_8^1=0.893668  y_9^1=0.989896  y_10^1=0.882937  y_11^1=0.925353  y_12^1=0.902882  y_13^1=0.515881  y_14^1=0.199376  y_15^1=0.199376 

For the vehicle type: 0

 ----- Min s-t cut -----

For the vehicle type: 1

 ----- Min s-t cut -----
=> A min s-t cut, No. 7
+ x_{3,0}^1+ x_{3,1}^1+ x_{3,2}^1+ x_{3,4}^1+ x_{3,5}^1+ x_{3,6}^1+ x_{3,7}^1+ x_{3,8}^1+ x_{3,10}^1+ x_{3,11}^1+ x_{3,12}^1+ x_{3,13}^1+ x_{3,14}^1+ x_{3,15}^1+ x_{9,0}^1+ x_{9,1}^1+ x_{9,2}^1+ x_{9,4}^1+ x_{9,5}^1+ x_{9,6}^1+ x_{9,7}^1+ x_{9,8}^1+ x_{9,10}^1+ x_{9,11}^1+ x_{9,12}^1+ x_{9,13}^1+ x_{9,14}^1+ x_{9,15}^1 >= y_3^1

=> A min s-t cut, No. 8
+ x_{7,0}^1+ x_{7,1}^1+ x_{7,2}^1+ x_{7,3}^1+ x_{7,4}^1+ x_{7,5}^1+ x_{7,6}^1+ x_{7,9}^1+ x_{7,10}^1+ x_{7,11}^1+ x_{7,12}^1+ x_{7,13}^1+ x_{7,14}^1+ x_{7,15}^1+ x_{8,0}^1+ x_{8,1}^1+ x_{8,2}^1+ x_{8,3}^1+ x_{8,4}^1+ x_{8,5}^1+ x_{8,6}^1+ x_{8,9}^1+ x_{8,10}^1+ x_{8,11}^1+ x_{8,12}^1+ x_{8,13}^1+ x_{8,14}^1+ x_{8,15}^1 >= y_7^1

=> A min s-t cut, No. 9
+ x_{8,0}^1+ x_{8,1}^1+ x_{8,2}^1+ x_{8,3}^1+ x_{8,4}^1+ x_{8,5}^1+ x_{8,6}^1+ x_{8,7}^1+ x_{8,9}^1+ x_{8,10}^1+ x_{8,11}^1+ x_{8,12}^1+ x_{8,13}^1+ x_{8,14}^1+ x_{8,15}^1 >= y_8^1

Root_bestbound = 82.1522

     0     2   84.18465    0   78          -   84.18465      -     -    3s
*   62    38              59     149.3550000   94.32514  36.8%  13.4    3s
*  592   208               9     148.3258000  115.13110  22.4%  15.0    3s

Cutting planes:
  User: 5

Explored 1952 nodes (30239 simplex iterations) in 4.84 seconds
Thread count was 1 (of 8 available processors)

Solution count 2: 148.326 149.355

Optimal solution found (tolerance 1.00e-04)
Best objective 1.483258000000e+02, best bound 1.483258000000e+02, gap 0.0000%

User-callback calls 4620, time in user-callback 3.02 sec

From the output, it shows that Gurobi calls the callback function twice in the root node and there are 9 cuts found in which 5 cuts are added in the end from the final statistics. After looking through the found cuts, the No.1 cut found in the 1st calling callback is the same as the No.7 cut found in the 2nd calling callback. Does it make sense? Also, from the output of the 2nd calling callback, the values of x- and y- variables printed at the beginning are different from the ones in the first calling, it seems like some cuts found in the 1st callback are already added and applied when implementing the 2nd calling. No?

I would appreciate any suggestion.

Thank you,

Ellen