<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE article PUBLIC "-//NLM//DTD JATS (Z39.96) Journal Publishing DTD v1.0 20120330//EN" "JATS-journalpublishing1.dtd"><article xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink" article-type="research-article"><front><journal-meta><journal-id journal-id-type="publisher-id">INFORMATICA</journal-id><journal-title-group><journal-title>Informatica</journal-title></journal-title-group><issn pub-type="epub">0868-4952</issn><issn pub-type="ppub">0868-4952</issn><publisher><publisher-name>VU</publisher-name></publisher></journal-meta><article-meta><article-id pub-id-type="publisher-id">INF41-215</article-id><article-id pub-id-type="doi">10.3233/INF-1993-41-215</article-id><article-categories><subj-group subj-group-type="heading"><subject>Research article</subject></subj-group></article-categories><title-group><article-title>How to choose a pivot element in simplex method?</article-title></title-group><contrib-group><contrib contrib-type="Author"><name><surname>Ubi</surname><given-names>Evald</given-names></name><xref ref-type="aff" rid="j_INFORMATICA_aff_000"/></contrib><aff id="j_INFORMATICA_aff_000">Dep. of Economics, Tallinn Technical University, EE 0026 Tallinn, Ehitajate St. 5, Estonia</aff></contrib-group><pub-date pub-type="epub"><day>01</day><month>01</month><year>1993</year></pub-date><volume>4</volume><issue>1-2</issue><fpage>217</fpage><lpage>226</lpage><abstract><p>New computational rules of the simplex method are represented. They differ from classical rules in the sense that the column corresponding to the objective function is also transformed and first the pivot row and then the pivot column is determined. In this case the most negative element in pivot row can be chosen for pivot element. In evaluating procedure systems equivalent to systems appearing in classical simplex method are used and theoretically they determine the-same sequence of basic solutions. The calculations are more precise due to such choice of pivot element and it is assured also by the results of test-problems.</p></abstract><kwd-group><label>Keywords</label><kwd>pivot element</kwd><kwd>simplex method</kwd><kwd>ill-conditioned problem of linear programming</kwd></kwd-group></article-meta></front></article>