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Re: [Outer [Times, , ] ] Question


Hi,

remove the MatrixForm[], MatrixForm[] is
a format function that wrap around your expression
 and hinder Plus[] to work
as expected.

Regards
  Jens

MichaelSMcCain at cs.com wrote:
> 
> Hi:
> 
> I want to take a Column Vector and multiply it by a Row Vector to create an
> "Outer" Matrix.
> 
> In other words, I want to take a 5x1 Column Vector and multiply it by a 1x4
> Row Vector and output a 5x4 Matrix.
> 
> I then want to add several of these Matrices together and obtain a "final"
> Matrix.
> 
> I tried the following:
> 
> x1 = {1, -1, -1, 1, 1};
> y1 = {1, 1, -1, -1};
> 
> x2 = {-1, 1, -1, 1, -1};
> y2 = {1, -1, 1, -1};
> 
> x3 = {1, 1, -1, -1, 1};
> y3 = {-1, -1, 1, 1};
> 
> m1 = MatrixForm[Outer [Times, x1, y1] ]
> m2 = MatrixForm[Outer [Times, x2, y2] ]
> m3 = MatrixForm[Outer [Times, x3, y3] ]
> 
> mm = m1 + m2 + m3
> 
> MatrixForm[mm]
> 
> The output that I get is incorrect and does not combine into a single Matrix.
> 
> What am I doing wrong?
> 
> Thanks,
> 
> Mike McCain
> MichaelSMcCain at cs.com


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