[数学建模] Python+Gurobi - 从零开始学习优化建模线性规划模型 (LP)
最编程
2024-04-20 18:30:45
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from gurobipy import * # 在Python中调用gurobi求解包
Max_Obj=1 # 用于判定目标函数求最大值还是求最小值
M_LP=Model("LP") #线性规划问题
# 变量声明
OP =M_LP.addVar(lb=-GRB.INFINITY,ub=GRB.INFINITY, name="OP")
x1 =M_LP.addVar(lb=0,ub=5, name="x1")
x2 =M_LP.addVar(lb=0,ub=3, name="x2")
x3 =M_LP.addVar(lb=0,ub=2, name="x3")
# 对变量边界进行限定的第二种写法：以x1为例
# M_LP.addConstr(x1>=0,"Bound_Con11")
# M_LP.addConstr(x1<=5,"Bound_Con12")
# 设置目标函数
if Max_Obj==0:
M_LP.setObjective(x1+2*x2-3*x3,GRB.MINIMIZE)
else:
M_LP.setObjective(x1+2*x2-3*x3,GRB.MAXIMIZE)
# 添加约束
M_LP.addConstr(x1+2*x2<=3,"Con1")
M_LP.addConstr(x2+x3<=2,"Con2")
M_LP.addConstr(x1+x2+x3==4,"Con3")
# Optimize model
M_LP.optimize()
M_LP.write("LP.lp")
print('**************')
print(' The optimal solution ')
print('**************')
print('OP is :',M_LP.ObjVal) # 输出目标值
print('x1 is :',x1.x) # .x 用于输出 X1 的值
print('x2 is :',x2.x)
print('x3 is :',x3.x)