[英]Cplex Error: Adding trivial infeasible linear constraint
I want to solve an integer programming model with cplex python.我想用 cplex python 解决整数编程模型。 I have this model:
我有这个模型:
a and h are matrixes with 0s and 1s. a 和 h 是具有 0 和 1 的矩阵。 p is a set of numbers.
p 是一组数字。 here is a part of my cplex code for this model:
这是我用于此模型的 cplex 代码的一部分:
p=[i for i in range (len(h))]
x=mdl.binary_var_dict(p,name='x')
#objective
mdl.minimize(0)
#constraints
#1
mdl.add_constraints(mdl.sum(h[i][k]*x[i] for i in p)==4 for k in T)
#2
mdl.add_constraints(mdl.sum(a[i][k]*x[i] for i in p)==4 for k in T)
mdl.print_information()
Solution = mdl.solve(log_output=False)
mdl.get_solve_status()
print(Solution)
When I run the program I get this error:当我运行程序时,我收到此错误:
Error: Adding trivial infeasible linear constraint: 0 == 4, rank: 1
Error: Adding trivial infeasible linear constraint: 0 == 4, rank: 1
Error: Adding trivial infeasible linear constraint: 0 == 4, rank: 23
Error: Adding trivial infeasible linear constraint: 0 == 4, rank: 23
'h' is a 600*22 matrix and 'a' is reverse of h(if there's a 1 (or 0) in h, it is 0 (or 1) in a). 'h' 是一个 600*22 的矩阵,'a' 是 h 的倒序(如果 h 中有 1(或 0),则 a 中的值为 0(或 1))。 A sample of h:
h 的样本:
[1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 1, 0, 0, 1, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0],
[1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0, 0, 1, 0, 1, 0]]
I don't understand where is the problem.我不明白问题出在哪里。
The error messages tells you what happens: you added a constraint that is trivially infeasible, ie, that can obviously not be satisfied.错误消息会告诉您发生了什么:您添加了一个非常不可行的约束,即,显然无法满足。 From the error message it seems you added some
== 4
constraints with an empty left-hand side.从错误消息看来,您添加了一些
== 4
约束,左侧为空。
From your code it looks that this would happen if p
is empty.从您的代码看来,如果
p
为空,则会发生这种情况。
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