RE: matrix times a vector

*To*: mathgroup at smc.vnet.net*Subject*: [mg49030] RE: [mg49002] matrix times a vector*From*: "David Park" <djmp at earthlink.net>*Date*: Tue, 29 Jun 2004 04:50:05 -0400 (EDT)*Sender*: owner-wri-mathgroup at wolfram.com

David, Is this what you want? vector = {x, y}; matrix = {{a, b}, {c, d}}; vector.matrix {a x + c y, b x + d y} Or maybe... vector .HoldForm /@ matrix % // ReleaseHold x {a, b} + y {c, d} {a x + c y, b x + d y} David Park djmp at earthlink.net http://home.earthlink.net/~djmp/ From: David Salomon [mailto:david.salomon at csun.edu] To: mathgroup at smc.vnet.net Question: The input {{a,b}, {c,d}}.{x,y} generates the output {a x+b y,c x+d y}. How can I get the output x{a,b}+y{c,d} ? This is a special case of lists with two elements. How can I extend this computation in an elegant way to lists with N elements? with thanks, |David Salomon | | |Computer Science Dept. dsalomon at csun.edu | |California State University http://www.ecs.csun.edu/~dxs | |Northridge, CA 91330-8281 (818) 677-4954 | |USA fax (818) 677-7208 | | | | Macintosh --- because you can see right through windows. |