[英]How to Formulate a Pulp Objective Function with a max operator
我正在尝试为 PuLP 中的成本优化制定一个目标函数,其中将数组的最大值添加到目标函数中。 请忽略缩进。
#Decision Variables
allocation_vars = LpVariable.dicts(
'Allocation',
[(i,j,k) for i in TruckTypes for j in Days for k in RS],
0,
LpInteger
)
#Objective Function
for i in TruckTypes:
for j in Days:
prob += max(allocation_vars[(i, j, k)] * TransCost[i][k] for k in RS)
尝试运行上述程序时出现以下错误:
prob += max(allocation_vars[(i, j, k)] * TransCost[i][k] for k in RS)
TypeError: '>' not supported between instances of 'LpAffineExpression' and 'LpAffineExpression'
正如@AirSquid所说,您应该重新制定。
请尝试以下操作:
m[i][j]
,将其添加到目标函数中;m = LpVariable.dicts(
'maxCosts',
[(i,j) for i in TruckTypes for j in Days],
0,
LpInteger
)
prob += lpSum([m[i][j] for j in Days for j in TruckTypes])
for i in TruckTypes:
for j in Days:
for k in RS:
prob += allocation_vars[(i,j,k)]*TransCost[i][k] <= m[i][j]
假设您有一个最小化问题,这将与max
完全相同:它会尽可能地减少m[i][j]
,并且要减少更多,它将尝试减少所有allocation_vars[(i,j,k)]*TransCost[i][k]
。
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