sch_add_relations {criticalpath}

Add Relations

Description

Combine several vectors for relation and their attributes into a tibble and add relations between activities to a schedule.

Usage

sch_add_relations(sch, from, to, type = "FS", lag = 0L, ...)

Arguments

sch

A schedule object.

from

The id of predecessor activity.

to

The id of successor activity.

type

Specifies the relation type between activities. The default type is FS and its value may be: FS, FF, SS, SF.

lag

The time period between activities that the successor activity to must be advanced after activity from has been finished.

...

One or more vectors for associated relation attributes.

Details

An relation tibble, or rtb, has at least the following columns:

• from (of type integer): The id of predecessor activity. Must exist an activity with from id.

• to (of type integer): The id of successor activity. Must exist an activity with to id.

• type (of type character) Specifies the relation type between activities. The default type is FS and its value may be: FS, FF, SS, SF, that means:

  • FS: Finish-Start relation. Activity 'to' id can only start after the finish of activity 'from' id.

  • FF: Finish-Finish relation. Activity 'to' id must finish together with activity 'from' id.

  • SS: Start-Start relation. Activity 'to' id must start together with activity 'from' id.

  • SF: Start-Finish relation. Activity 'to' id must finish when activity 'from' id starts.

• lag (of type integer): The time period between activities that the successor activity to must be advanced after activity from has been finished. The value may be negative, in such case, the activity 'to' will be anticipated 'lag' time periods. It must be an integer, less than, equal or greater than zero. If lag is not defined, it is assumed to be zero.

An arbitrary number of additional columns containing data attributes can be part of the rtb, so long as they follow the aforementioned columns.

Value

A schedule with a relation tibble (rtb) added.

See Also

sch_title(), sch_reference(), sch_add_relation(), sch_nr_relations(), sch_has_any_relation(), sch_new(), sch_plan(), sch_add_activities(), sch_validate().

Examples

sch <- sch_new() %>%
  sch_title("Project 1: Cost Information System") %>%
  sch_reference(
    "VANHOUCKE, Mario. Integrated project management and control:
    first comes the theory, then the practice.Gent: Springer, 2014, p. 6"
  ) %>%
  sch_add_activities(
    id        = 1:17,
    name      = paste("a", as.character(1:17), sep=""),
    duration  = c(1L,2L,2L,4L,3L,3L,3L,2L,1L,1L,2L,1L,1L,1L,1L,2L,1L)
  ) %>%
  sch_plan()
sch_has_any_relation(sch) # FALSE
sch_nr_relations(sch) # 0
sch_duration(sch) # 4

sch %<>%
  sch_add_relations(
    from = c(1L, 1L, 2L, 2L, 2L, 3L, 3L, 3L,  3L,  4L,  5L,  6L,
             7L,  8L,  9L, 10L, 11L, 11L, 12L, 12L, 13L, 13L, 14L, 14L, 15L, 15L),
    to   = c(2L, 3L, 4L, 5L, 6L, 7L, 8L, 9L, 10L, 11L, 11L, 11L,
             12L, 13L, 14L, 15L, 16L, 17L, 16L, 17L, 16L, 17L, 16L, 17L, 16L, 17L)
  ) %>%
  sch_plan()
sch_has_any_relation(sch) # TRUE
sch_nr_relations(sch) # 26
sch_duration(sch) # 11