Function cp::GroupOfPrevious(sequentialResource, scheduledActivity, firstValue, absentValue)

# cp::GroupOfPrevious

The function cp::GroupOfPrevious refers to the group of the previous activity in a sequence of activities. The group of an activity is specified in the group definition attribute of the sequential resource to ensure the sequencing. For a resource $$r$$, an activity $$a$$, groups $$f$$ and $$d$$, the function cp::GroupOfPrevious(r,a,f,d) returns

• $$d$$ if $$a$$ is absent,

• $$f$$ if $$a$$ is present and scheduled as the first activity on $$r$$, and

• $$GroupOf(r,p)$$ if $$a$$ is present and not scheduled as the first activity on $$r$$, and $$p$$ is the previous activity of $$a$$ scheduled on $$r$$.

cp::GroupOfPrevious(
sequentialResource,  ! (input) an expression
scheduledActivity,   ! (input) an expression
firstValue,          ! (optional) an expression
absentValue          ! (optional) an expression
)


## Arguments

sequentialResource

An expression that results in a sequential resource.

scheduledActivity

An expression that results in an activity.

firstValue

An optional expression that results in a group. The default value of this expression is the first element of the group set of the sequential resource.

absentValue

An optional expression that results in a group. The default value of this expression is the first element of the group set of the sequential resource.

## Return Value

This function returns a group.