<?xml version='1.0' encoding='UTF-8'?><codeBook xmlns="ddi:codebook:2_5" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="ddi:codebook:2_5 https://ddialliance.org/Specification/DDI-Codebook/2.5/XMLSchema/codebook.xsd" version="2.5" xml:lang="en"><docDscr><citation><titlStmt><titl xml:lang="en">Triangular Grid Instances for the Euclidean Steiner Tree Problem</titl><IDNo agency="DOI">doi:10.60507/FK2/XLGFI4</IDNo></titlStmt><distStmt><distrbtr source="archive">bonndata</distrbtr><distDate>2024-05-24</distDate></distStmt><verStmt source="archive"><version date="2024-05-24" type="RELEASED">1</version></verStmt><biblCit>Hougardy, Stefan, 2024, "Triangular Grid Instances for the Euclidean Steiner Tree Problem", https://doi.org/10.60507/FK2/XLGFI4, bonndata, V1</biblCit></citation></docDscr><stdyDscr><citation><titlStmt><titl xml:lang="en">Triangular Grid Instances for the Euclidean Steiner Tree Problem</titl><IDNo agency="DOI">doi:10.60507/FK2/XLGFI4</IDNo></titlStmt><rspStmt><AuthEnty affiliation="University of Bonn">Hougardy, Stefan</AuthEnty></rspStmt><prodStmt/><distStmt><distrbtr source="archive">bonndata</distrbtr><contact affiliation="University of Bonn" email="shougard@uni-bonn.de">Hougardy, Stefan</contact><depositr>Hougardy, Stefan</depositr><depDate>2024-05-21</depDate></distStmt><holdings URI="https://doi.org/10.60507/FK2/XLGFI4"/></citation><stdyInfo><subject><keyword xml:lang="en">Computer and Information Science</keyword><keyword xml:lang="en">Mathematical Sciences</keyword></subject><abstract xml:lang="en">This data set contains triangular nxk arrays with 2&lt;=n, k&lt;=10 using the TSPLIB-format.

The instances where generated as part of the master's thesis of Daphne Rohrssen 
written 2022 under the supervision of Stefan Hougardy at the University of Bonn. 

Some of these instances are very hard to solve exactly for GeoSteiner 5.1. For example the 4x9 instance with 36 vertices needs more than 10 days of CPU time. SCIP-JACK 2.1 solves this instance within 20 minutes. However, one should be aware of the fact that both codes have numerical problems and cannot guarantee optimality  of the solutions. With SCIP-JACK this seems to happen more often than with GeoSteiner.</abstract><sumDscr/></stdyInfo><method><dataColl><sources/></dataColl><anlyInfo/></method><dataAccs><setAvail/><useStmt/><notes type="DVN:TOU" level="dv">&lt;a href="http://creativecommons.org/licenses/by/4.0">CC BY 4.0&lt;/a></notes></dataAccs><othrStdyMat/></stdyDscr><otherMat ID="f4488" URI="https://bonndata.uni-bonn.de/catalog/downloads/4488/readme.txt" level="datafile"><labl>readme.txt</labl><txt>readme file</txt><notes level="file" type="DATAVERSE:CONTENTTYPE" subject="Content/MIME Type">text/plain</notes></otherMat><otherMat ID="f4489" URI="https://bonndata.uni-bonn.de/catalog/downloads/4489/triangular_instances.zip" level="datafile"><labl>triangular_instances.zip</labl><txt>Steiner tree instances for triangular grids</txt><notes level="file" type="DATAVERSE:CONTENTTYPE" subject="Content/MIME Type">application/zip</notes></otherMat></codeBook>