from scipy.optimize import linprog
import time
import numpy as np
'''
目标函数：
min z= -x1 + 4 x2 

约束条件：
-3x1 + x2 < = 6
x1 + 2x2 <= 4 
x2 >= -3 

'''
begin = time.time()
c=[-1,4]
A=[[-3,1],[1,2]]
b=[[6],[4]]
bounds=((None , None),(-3,None))
res= linprog(c,A,b,None,None,bounds)
end= time.time()
print("结果为：",res.fun)
print("x的值位",res.x," ",type(res.x))
print(end-begin,"\n",'----------------------------------------')
'''
线性规划问题
 max z = x1  - 2x2 - 3x3 
 约束条件
 -2x1 + x2 + x3 <= 9
 -3x1 + x2 + 2x3 >= 4 
 4x1 -2x2 -x3 = -6 
 x1 >= -10 ,x2 >=0
'''
'''
scipy标准形式：
min w= -x1 + 2x2  + 3x3 

约束： 
-2x1 + x2 + x3 <= 9
3x1 - x2 - 2x3 <= -4
'''
c= (-np.array([1,-2,-3])).tolist()
A=[[-2,1,1],[-3,1,2]]
A[1]= (-np.array(A)[1]).tolist()
b= [[9],[4]]
b[1]=(-np.array(b[1])).tolist()
Aeq=[[4,-2,-1]]
beq =[[-6]]
LB =[-10,0,None]
UB = [None]*len(c)
bounds= tuple(zip(LB,UB))
res= linprog(c,A,b,Aeq,beq,bounds)
end= time.time()
print("结果为：",res.fun)
print("x的值位",res.x," ",type(res.x))
print(end-begin,"\n",'----------------------------------------')
print(res)