Combining Matrices

*To*: mathgroup at smc.vnet.net*Subject*: [mg65017] Combining Matrices*From*: Gregory Lypny <gregory.lypny at videotron.ca>*Date*: Sat, 11 Mar 2006 05:16:05 -0500 (EST)*Sender*: owner-wri-mathgroup at wolfram.com

Hello Everyone, I'm trying to figure out how to combine an n x p matrix and an n x q matrix to form an n x (p + q) matrix. I found one way, shown in the second last line of the code below, but I have no idea why it works, and I'm wondering whether there is a more direct way. The example takes 3 x 4 matrix A and combines it with 3 x 2 matrix B to form 3 x 6 matrix X. Any thoughts would be most appreciated. Gregory Clear[X] n = 3; p = 4; q = 2; A = Array[a, {n, p}]; B = Array[b, {n, q}]; (X = Transpose[Flatten[{{Transpose[A], Transpose[B]}}, 2]]) // MatrixForm Dimensions[X]