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RE: matrix times a vector

• To: mathgroup at smc.vnet.net
• Subject: [mg49022] RE: [mg49002] matrix times a vector
• From: "Wolf, Hartmut" <Hartmut.Wolf at t-systems.com>
• Date: Tue, 29 Jun 2004 04:49:50 -0400 (EDT)
• Sender: owner-wri-mathgroup at wolfram.com

>-----Original Message-----
>From: David Salomon [mailto:david.salomon at csun.edu]
To: mathgroup at smc.vnet.net
>Sent: Monday, June 28, 2004 10:14 AM
>To: mathgroup at smc.vnet.net
>Subject: [mg49022] [mg49002] matrix times a vector
>
>
>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                                                 
>|                                                   

[...]

Move from Dot to Times:

In[1]:= {{a, b}, {c, d}}.{x, y}
Out[1]= {a x + b y, c x + d y}

In[2]:= {{a, b}, {c, d}}{x, y}
Out[2]= {{a x, b x}, {c y, d y}}


--
Hartmut Wolf