Optimization 影子价格-XPRESS-纸浆

我正在尝试使用纸浆和XPRESS解算器获得LP问题的影子价格

对于CBC解算器，.pi命令可以正常工作：

import pulp
my_lp_problem = pulp.LpProblem("My LP Problem", pulp.LpMinimize)
a = pulp.LpVariable("L",lowBound=-10, upBound=10, cat='Continuous')
my_lp_problem += a<= 2
my_lp_problem += a >= -5
my_lp_problem += a
my_lp_problem.solve(pulp.PULP_CBC_CMD())
for name, c in list(my_lp_problem.constraints.items()):
    print(c.pi)

但是，使用XPRESS：

import pulp
my_lp_problem = pulp.LpProblem("My LP Problem", pulp.LpMinimize)
a = pulp.LpVariable("L",lowBound=-10, upBound=10, cat='Continuous')
my_lp_problem += a<= 2
my_lp_problem += a >= -5
my_lp_problem += a
my_lp_problem.solve(pulp.XPRESS())
for name, c in list(my_lp_problem.constraints.items()):
    print(c.pi)

有人知道如何解决这个问题吗

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谢谢大家!

就我所见，目前纸浆中的XPRESS api不支持获得影子价格。在项目的网站上随意打开一个问题：

import pulp
my_lp_problem = pulp.LpProblem("My LP Problem", pulp.LpMinimize)
a = pulp.LpVariable("L",lowBound=-10, upBound=10, cat='Continuous')
my_lp_problem += a<= 2
my_lp_problem += a >= -5
my_lp_problem += a
my_lp_problem.solve(pulp.XPRESS())
for name, c in list(my_lp_problem.constraints.items()):
    print(c.pi)

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