A measurement of the top quark pair-production cross section in the lepton+jets decay channel is presented. It is based on 4.6  fb−1 of √𝑠 =7  TeV 𝑝⁢𝑝 collision data collected during 2011 by the ATLAS experiment at the CERN Large Hadron Collider. A three-class, multidimensional event classifier based on support vector machines is used to differentiate 𝑡⁢¯𝑡 events from backgrounds. The 𝑡⁢¯𝑡 production cross section is found to be 𝜎𝑡⁢¯𝑡=168.5±0.7⁢(stat)⁢ +6.2−5.9⁢(syst)⁢ +3.4−3.2⁢(lumi)  pb. The result is consistent with the Standard Model prediction based on QCD calculations at next-to-next-to-leading order.