XESTT is an XML data format for defining instances and solutions of employee scheduling problems. It is an extension of XHSTT, the standard format for expressing instances and solutions of high school timetabling problems. Although the `ES' in XESTT stands for `employee scheduling', at present the XESTT project is limited to nurse rostering.
An XESTT archive is an XML file containing any number of instances of the nurse rostering problem, together with any number of sets of solutions to those instances, all expressed in the XESTT format. The following archives, created by the NRConv program, are available here:
COI.xml (10M). Contains XESTT versions of 27 of the 28 `original' instances and 65 of the 66 solutions to those instances posted by Tim Curtois on his nurse rostering site. The omitted instance is HED01b, omitted because it is almost the same as HED01, and because Curtois omitted it in a recent paper about these instances. The omitted solution is a solution to HED01b.
INRC1-Long-and-Medium.xml (7M) and INRC1-Sprint.xml (4M). Two archives containing XESTT versions of the 15 long, 15 medium, and 30 sprint instances of the First International Nurse Rostering Competition, and 60 solutions (one for each instance) posted by the GOAL group here.
INRC2-4.xml (10M) and INRC2-8.xml (17M). These are 4-week and 8-week instances from the Second International Nurse Rostering Competition which have been tackled by several authors, along with solutions provided by Jeremy Omer. No one-week instances are posted here. However, NRConv includes a converter for the full INRC2 format, including scenario, history, and weekly instance files, for those who want to make their own.
You can download this whole site (the 20 January 2020 version) as a gzipped tar file (8M). It unpacks to directory xestt, containing the XESTT archives, and the source instances and solutions that the archives convert. File xestt/README explains what is where. The old (1 November 2018) version is here (8M).
The HSEval High School Timetable Evaluator, a web service that evaluates solutions to XHSTT and XESTT instances. It also has pages that give detailed technical specifications of the XHSTT and XESTT formats.
KHE, a software platform on which efficient solvers for XHSTT and XESTT instances can be built. It includes the NRConv program that converts instances and solutions in other formats to XESTT. You only need NRConv if you plan to do your own conversions.
I've tried my hand at solving all the instances posted here, using my KHE20 (formerly KHE18) solver. My latest results, obtained with Version 2.4 of KHE on 20 January 2020, can be found in this directory along with my older results. The XESTT archive files containing my latest results have names beginning with KHE20-2020-01-20. I've written two papers about solving: KHE18: A Solver for Nurse Rostering, which appeared in PATAT 2018, and KHE20: An Improved Solver for Nurse Rostering, which I have submitted to PATAT 2020. There is also a supplement to this second paper which is available here only.