Examples overview

Timefold has several examples. In this manual we explain mainly using the n queens example and cloud balancing example. So it is advisable to read at least those sections.

Some of the examples solve problems that are presented in academic contests. The Contest column in the following table lists the contests. It also identifies an example as being either realistic or unrealistic for the purpose of a contest. A realistic contest is an official, independent contest:

  • that clearly defines a real-world use case.

  • with real-world constraints.

  • with multiple, real-world datasets.

  • that expects reproducible results within a specific time limit on specific hardware.

  • that has had serious participation from the academic and/or enterprise Operations Research community.

Realistic contests provide an objective comparison of Timefold with competitive software and academic research.

The source code of all these examples is available in the distribution zip under examples/sources and also in git under timefold/timefold-solver-examples.

Table 1. Examples overview
Example Domain Size Contest Special features used

N queens

  • 1 entity class

    • 1 variable

  • Entity ⇐ 256

  • Value ⇐ 256

  • Search space ⇐ 10^616

None

Cloud balancing

  • 1 entity class

    • 1 variable

  • Entity ⇐ 2400

  • Value ⇐ 800

  • Search space ⇐ 10^6967

  • No

  • Defined by us

Traveling salesman

  • 1 entity class

    • 1 chained variable

  • Entity ⇐ 980

  • Value ⇐ 980

  • Search space ⇐ 10^2504

Tennis club scheduling

  • 1 entity class

    • 1 variable

  • Entity ⇐ 72

  • Value ⇐ 7

  • Search space ⇐ 10^60

  • No

  • Defined by us

Meeting scheduling

  • 1 entity class

    • 2 variables

  • Entity ⇐ 10

  • Value ⇐ 320 and ⇐ 5

  • Search space ⇐ 10^320

  • No

  • Defined by us

Course timetabling

  • 1 entity class

    • 2 variables

  • Entity ⇐ 434

  • Value ⇐ 25 and ⇐ 20

  • Search space ⇐ 10^1171

Machine reassignment

  • 1 entity class

    • 1 variable

  • Entity ⇐ 50000

  • Value ⇐ 5000

  • Search space ⇐ 10^184948

Vehicle routing

  • 1 entity class

    • 1 list variable

  • 1 shadow entity class

    • 3 automatic shadow variable

  • Entity ⇐ 55

  • Value ⇐ 2750

  • Search space ⇐ 10^8380

Vehicle routing with time windows

  • All of Vehicle routing

  • 1 shadow variable

  • Entity ⇐ 55

  • Value ⇐ 2750

  • Search space ⇐ 10^8380

Project job scheduling

  • 1 entity class

    • 2 variables

    • 1 shadow variable

  • Entity ⇐ 640

  • Value ⇐ ? and ⇐ ?

  • Search space ⇐ ?

Hospital bed planning

  • 1 entity class

    • 1 nullable variable

  • Entity ⇐ 2750

  • Value ⇐ 471

  • Search space ⇐ 10^6851

Task assigning

  • 1 entity class

    • 1 list variable

  • 1 shadow entity class

    • 1 automatic shadow variable

    • 1 shadow variable

  • Entity ⇐ 20

  • Value ⇐ 500

  • Search space ⇐ 10^1168

  • No

  • Defined by us

Exam timetabling

  • 2 entity classes (same hierarchy)

    • 2 variables

  • Entity ⇐ 1096

  • Value ⇐ 80 and ⇐ 49

  • Search space ⇐ 10^3374

Nurse rostering

  • 1 entity class

    • 1 variable

  • Entity ⇐ 752

  • Value ⇐ 50

  • Search space ⇐ 10^1277

Traveling tournament

  • 1 entity class

    • 1 variable

  • Entity ⇐ 1560

  • Value ⇐ 78

  • Search space ⇐ 10^2301

  • Unrealistic

  • TTP

Conference scheduling

  • 1 entity class

    • 2 variables

  • Entity ⇐ 216

  • Value ⇐ 18 and ⇐ 20

  • Search space ⇐ 10^552

  • No

  • Defined by us

Flight crew scheduling

  • 1 entity class

    • 1 variable

  • 1 shadow entity class

    • 1 automatic shadow variable

  • Entity ⇐ 4375

  • Value ⇐ 750

  • Search space ⇐ 10^12578

  • No

  • Defined by us