如何在 docplex (python) 中启动区间变量边界？

Question

我有以下 OPL 代码，需要在 docplex 中实现它 (python)，我是该领域的新手...

using CP;
dvar interval I1 in 0..20;
dvar interval I2 in 0..20;
dvar interval I3 in 0..20;

dvar int over1;
dvar int start1;
dvar int end1;

dvar interval artificialInterval;

maximize over1;

subject to
{

    over1==overlapLength(I1,I2);

    start1==maxl(startOf(I1),startOf(I2));

    end1==minl(endOf(I1),endOf(I2));

    startOf(artificialInterval)==start1;
    endOf(artificialInterval)==end1;

    over1==overlapLength(I3,artificialInterval);
}

问题出现在行 startOf(artificialInterval)==start1; 和 endOf(artificialInterval)==end1;

这是我所做的：

mdl=CpoModel()

   I1=mdl.interval_var(define its parameters)
   I2=mdl.interval_var(define its parameters)
   I3=mdl.interval_var(define its parameters)

   over1=mdl.integer_var()
   start1=mdl.integer_var()
   end1=mdl.integer_var()

   artificialInterval=mdl.interval_var()

   over1=mdl.overlapLength(I1,I2)
   start1=mdl.max(mdl.start_of(I1),mdl.start_of(I2))
   end1=mdl.min(mdl.end_of(I1),mdl.end_of(I2))

   mdl.start_of(artificialInterval) =start1
   mdl.end_of(artificialInterval) =end1

   over1=mdl.overlapLength(I3,artificialInterval)

   obj = mdl.maximize(over1)
   mdl.solve()

有了这个我有语法错误"SyntaxError: can't assign to function call" 所以我尝试使用 set_start(start1) 但我认为我也没有很好地使用它......

如有任何提示，我们将不胜感激。谢谢，

Answer 1

from docplex.cp.model import CpoModel 
mdl=CpoModel()

I1=mdl.interval_var(0,10)
I2=mdl.interval_var(0,10)
I3=mdl.interval_var(0,10)

over1=mdl.integer_var()
start1=mdl.integer_var()
end1=mdl.integer_var()

artificialInterval=mdl.interval_var()

mdl.add(over1==mdl.overlap_length(I1,I2))
start1=mdl.max(mdl.start_of(I1),mdl.start_of(I2))
end1=mdl.min(mdl.end_of(I1),mdl.end_of(I2))

mdl.add(mdl.start_of(artificialInterval) ==start1)
mdl.add(mdl.end_of(artificialInterval) ==end1)

mdl.add(over1==mdl.overlap_length(I3,artificialInterval))

obj = mdl.maximize(over1)
mdl.solve()

效果更好

如何在 docplex (python) 中启动区间变量边界？

How to initiate the interval variable bounds in docplex (python)?

optimization

cplex

docplex