Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: Combining Matrices

  • To: mathgroup at smc.vnet.net
  • Subject: [mg65061] Re: Combining Matrices
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Sun, 12 Mar 2006 23:59:41 -0500 (EST)
  • Organization: The Open University, Milton Keynes, UK
  • References: <duudan$ht1$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Gregory Lypny wrote:
> 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]
> 
Hi Gregory,

You could try *MapThread*

Clear[X]
n = 3; p = 4; q = 2;
A = Array[a, {n, p}];
B = Array[b, {n, q}];
MatrixForm[X = MapThread[Join, {A, B}]]
Dimensions[X]

Best regards,
/J.M.


  • Prev by Date: Re: Mathematica and Education
  • Next by Date: Re: Graphics3D polygon face colors
  • Previous by thread: Re: Combining Matrices
  • Next by thread: Re: Combining Matrices