zhang yanwei princetonmram yzhangmunichreamericacom thanks exactly want sincerely yanwei zhang department actuarial research modeling munich america tel 6092752176 email yzhangmunichreamericacom original message ling gary electronic trading mailtogary_lingmlcom sent wednesday august 06 2008 542 pm zhang yanwei princetonmram rhelprprojectorg subject r matrix multiplication hi yes way relatively easy using reduce note order use reduce need updatetodate version r im using 262 first matrices line correct dimensions ie m_1 x m_2 m_2 x m_3 m_n1 x m_n u get idea right ill use 4x4 square matrices example demo simulate list 4x4 matrices 10 matrices listofmatrices replicate10matrixrnorm164simplifyfalse power reduce functional programming reduce listofmatrices 1 2 3 4 1 32494000 67789481 49703126 39731644 2 02992145 39928493 24463129 30178451 3 02735238 7953889 6130237 9717463 4 07801092 3003660 1104163 5834807 lets check imperative programming mm listofmatrices1 listofmatrices1 mm mm mm 1 2 3 4 1 32494000 67789481 49703126 39731644 2 02992145 39928493 24463129 30178451 3 02735238 7953889 6130237 9717463 4 07801092 3003660 1104163 5834807 end demo cheers gary original message rhelpbouncesrprojectorg mailtorhelpbouncesrprojectorg behalf zhang yanwei princetonmram sent wednesday august 06 2008 502 pm rhelprprojectorg subject r matrix multiplication hi easy way cumulative matrix multipliation r whats syntex thanks sincerely yanwei zhang department actuarial research modeling munich america tel 6092752176 email yzhangmunichreamericacom alternative html version deleted ______________________________________________ rhelprprojectorg mailing list httpsstatethzchmailmanlistinforhelp please read posting guide httpwwwrprojectorgpostingguidehtml provide commented minimal selfcontained reproducible code message wattachments message may privileged confidential proprietary intended recipient please notify sender use share delete unless specifically indicated message offer sell solicitation investment products financial product service official confirmation transaction official statement merrill lynch subject applicable law merrill lynch may monitor review retain ecommunications ec traveling networkssystems laws country senderrecipient may impact handling ec ec may archived supervised produced countries country located message guaranteed secure errorfree message subject terms available following link httpwwwmlcomecommunications_terms messaging merrill lynch consent foregoing ______________________________________________ rhelprprojectorg mailing list httpsstatethzchmailmanlistinforhelp please read posting guide httpwwwrprojectorgpostingguidehtml provide commented minimal selfcontained reproducible code thu 07 aug 2008 085500 0400 r matrix multiplication