Originally posted by: sdormidontov

Is it possible to insert a decision variable as an index of array, that is extracting from dat file?

This code does not work for me. Where is a problem?

(ConductorToConnetionTrain[r][c] in Trains) => (
    (card(PossibleTrainSwitches[ConductorToConnetionTrain[r][c]][c]) >= 1) =>                                     
        (
                ConductorToConnetionTrain[r][c + 1] in PossibleTrainSwitches[ConductorToConnetionTrain[r][c]][c]
        )
);     

ConductorToConnectionTrain is a decision variable

PossibleTrainSwitches is a standard array from .dat file

The error is:

CP cannot extract expression ...

and indicates exactly on these strings that I provided.

Hi,

the problem is not indexing by a decision variable but using a set.

For example:

using CP;

 

{int} s[1..2]=[{1,2},{4,5}];

 

dvar int x in 1..2;

dvar int y in 1..10;

subject to

{

1<=x<=2;

y in s[x];

x==2;

}

is not allowed

But the following model that is equivalent is allowed:

using CP;

 

　

{int} s[1..2]=[{1,2},{4,5}];

 

int isIn[k in 1..10][i in 1..2]=(k in s[i])?1:0;

 

dvar int x in 1..2;

dvar int y in 1..10;

subject to

{

1<=x<=2;

//y in s[x];

isIn[y][x]==1;

 

x==2;

 

 

}

regards