Re: Multiplying a vector over multiple vectors

*To*: mathgroup at smc.vnet.net*Subject*: [mg91191] Re: Multiplying a vector over multiple vectors*From*: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>*Date*: Fri, 8 Aug 2008 07:18:38 -0400 (EDT)*References*: <g7ed6u$2pm$1@smc.vnet.net>

Hi, lst={{1,2}, {3,4}, {5,6}}; and {a, b}*# & /@ lst or Transpose[{a, b}*Transpose[lst]] Regards Jens Donald DuBois wrote: > How does one get a vector to distribute over > a list of vectors under multiplication? > > For example: > > {{1,2}, {3,4}, {5,6}} times {a,b} should > equal (under this operation) > > {{a, 2b}, {3a, 4b}, {5a, 6b}} > > If {a,b} is duplicated three times one can > use MapThread as in: > > MapThread[Times, {{{1, 2}, {3, 4}, {5, 6}}, {{a, b}, {a, b}, {a, b}}}] > > but duplicating {a,b} using Table is very slow > when the vectors are large (consisting of thousands > of elemets). > > Thanks in advance for any help you can give me. > > Don >