使用doopl的opl.set_input作为参数的正确方法不是元组

问题描述

我正在尝试在Python中运行CPLEX .mod文件。以下链接中提供了有关如何执行此操作的讲师：

How to run a .mod file (CPLEX) using python?

但是，似乎（也许）只有元组才从Python发送到CPLEX。就我而言，CPLEX .mod文件中有一个循环，如下所示：

for (var i = lowerBound; i <= upperBound; i++) {
...
}

我想将参数lowerBound和upperBound从Python发送到CPLEX .mod文件。为此目的，我在for循环之前的CPLEX .mod文件中定义了一个变量，如下所示：

var lowerBound = ...;
var upperBound = ...;

然后，我在Python中使用以下命令：

from doopl.factory import *
with create_opl_model(model="model.mod") as opl:
    opl.set_input("upperBound",50)
    opl.set_input("lowerBound",1)
    opl.run()

但出现以下错误：

ERROR at 17:18 model.mod: Scripting parser error: missing expression.

我想说的是，在CPLEX .mod中，第17和18行是：

var lowerBound = ...; 
var upperBound = ...;

问题：我想知道是否仅通过opl.set_input ()发送元组？为了理解这一点，我做了如下的事情：

在CPLEX .mod内部：

tuple bounds {
        int lowerBound;
        int upperBound;
        
    }

    
for (var i = lowerBound; i <= upperBound; i++) {
    ...
}

Python内部：

from doopl.factory import *

Bounds = [
    (1,50),]

with create_opl_model(model=" model.mod") as opl:
    opl.set_input("bounds",Bounds)
    opl.run()

但是这次，出现如下错误：

ERROR at 20:7 model.mod: Scripting parser error: missing ';' or newline between statements.

我想说的是，在CPLEX .mod文件中，第20行与元组边界的定义有关，即：

tuple bounds {
        int lowerBound;
        int upperBound;
        
    }

对此有什么解决方案？

解决方法

您需要使用元组集，但要使用

tuple bounds {
        int lowerBound;
        int upperBound;
        
    }

那不是你要做的。

您应该写

tuple typebounds {
        int lowerBound;
        int upperBound;
        
    }

{typebounds} bounds=...;

.mod文件中的

让我分享完整的example：

from doopl.factory import *
# Data

Buses=[
        (40,500),(30,400)
        ]

MinAndMax=[(1,5)]

# Create an OPL model from a .mod file
with create_opl_model(model="zootuplesetwithminandmax.mod") as opl:
    # tuple can be a list of tuples,a pandas dataframe...
    opl.set_input("buses",Buses)
    opl.set_input("singletonMinAndMax",MinAndMax)

    # Generate the problem and solve it.
    opl.run()

    # Get the names of post processing tables
    print("Table names are: "+ str(opl.output_table_names))

    # Get all the post processing tables as dataframes.
    for name,table in iteritems(opl.report):
        print("Table : " + name)
    for t in table.itertuples(index=False):
            print(t)

    # nicer display
    for t in table.itertuples(index=False):
        print(t[0]," buses ",t[1],"seats")

with zootuplesetwithminandmax.mod

int nbKids=300;

// a tuple is like a struct in C,a class in C++ or a record in Pascal
tuple bus
{
key int nbSeats;
float cost;
}

// This is a tuple set
{bus} buses=...;

tuple minandmax
{
int m;
int M;
}

{minandmax} singletonMinAndMax=...;

int minBuses=first(singletonMinAndMax).m;
int maxBuses=first(singletonMinAndMax).M;


// asserts help make sure data is fine
assert forall(b in buses) b.nbSeats>0;
assert forall(b in buses) b.cost>0;

// decision variable array
dvar int+ nbBus[buses] in minBuses..maxBuses;

// objective
minimize
 sum(b in buses) b.cost*nbBus[b];
 
// constraints
subject to
{
 sum(b in buses) b.nbSeats*nbBus[b]>=nbKids;
}

tuple solution
{
  int nbBus;
  int sizeBus;
}

{solution} solutions={<nbBus[b],b.nbSeats> | b in buses};

cplex opl python