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# disjunction_choose(?Start1, +Duration1, ?Start2, +Duration2, ?Flag)

Flag indicates which of the two non-overlapping tasks is scheduled as
first. Either the one with starting time Start1 and duration Duration1
(then the value of Flag is 1), or the second one with starting time Start2
and duration Duration2 (and the Flag is 2).
*?Start1*
- A finite domain variable or integer
*+Duration1*
- An integer
*?Start2*
- A finite domain variable or integer
*+Duration2*
- An integer
*?Flag*
- A variable or integer

## Description

This constraint can be used, if there are two tasks that have to be
scheduled on the same machine. It states which of the two tasks given
by their starting times and durations is scheduled as first. It is
activated whenever the maximum or minimum of domain variables Start1 or
Start2 resp. changes or the Flag is set to an integer.

### Fail Conditions

Fails if there is no possibility to schedule given two tasks in any
order under given conditions.
### Resatisfiable

No.
### Exceptions

*(4) instantiation fault *
- Duration1 or Duration2 is not instantiated.
*(5) type error *
- Duration1 or Duration2 or Flag is instantiated but not an integer.

## Examples

[eclipse 5]: [X, Y]::1..10, disjunction_choose(X, 5, Y, 7, F).
X = X[1..10]
Y = Y[1..10]
F = F[1, 2]
Delayed goals:
disjunction_choose_1(X[1..10], 5, Y[1..10], 7, F[1, 2])
yes.
[eclipse 6]: [X, Y]::1..10, disjunction_choose(X, 5, Y, 7, 1).
X = X[1..5]
Y = Y[6..10]
Delayed goals:
Y[6..10] - X[1..5]#>=5
disjunction_choose_1(X[1..5], 5, Y[6..10], 7, 1)
yes.
[eclipse 8]: [X, Y]::1..5, disjunction_choose(X, 5, Y, 7, 2).
no (more) solution.

## See Also

disjunctive / 3, disjunction / 5