Originally posted by: SystemAdmin

is there a way using "logical or - ||" between each constraint which are constructed by forall stament. for example:
x[1]=1 ||
x[2]=1 ||
x[3]=1 ||
x[4]=1 ||

how can i write these logical constraints by using forall?

forall(i in 1..4)x[i]==1|| doesn't works...
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Originally posted by: SystemAdmin

You could use the sum operator to do specify that the sum of variables x in 1..4 that have value 1 should be at least one:

sum(i in 1..4) (x[i] == 1) >= 1

Since (x[i] == 1) is a boolean variable in 0..1 (0 meaning false, and 1 meaning true), this sum has an equivalent semantic to the disjunction of your example.

Regards,
Stefano
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#OPLusingCPLEXOptimizer

Originally posted by: davidoff

If you are in a CP context, it is valid to write

using CP;
...
or(i in 1..4) x[i]==1

And using CPLEX as the engine, the formulation of the previous post is valid. Note that if your variables are boolean, you have a native linear simplification :

sum(i in 1..4) x[i] >=1

David
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Originally posted by: SystemAdmin

if i change the constraints like:

x[1][3][1]+x[3][2][1]=2||
x[1][4][1]+x[4][2][1]=2||
x[1][3][2]+x[3][2][2]=2||
x[1][4][2]+x[4][2][2]=2||
.
.
.
how can i make these logical constraints in closed form?
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