[Outer [Times, , ] ] Question

*To*: mathgroup at smc.vnet.net*Subject*: [mg45790] [Outer [Times, , ] ] Question*From*: MichaelSMcCain at cs.com*Date*: Sun, 25 Jan 2004 03:04:45 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

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

**Follow-Ups**:**Re: [Outer [Times, , ] ] Question***From:*Yasvir Tesiram <tesiramy@omrf.ouhsc.edu>