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Re: Matrix m x n

  • To: mathgroup at smc.vnet.net
  • Subject: [mg52773] Re: [mg52713] Matrix m x n
  • From: Bob Hanlon <hanlonr at cox.net>
  • Date: Mon, 13 Dec 2004 04:22:17 -0500 (EST)
  • Reply-to: hanlonr at cox.net
  • Sender: owner-wri-mathgroup at wolfram.com

f[A_] := 2*MatrixPower[A,2] + 3*A+2;

A ={{x11,x12},{x21,x22}};

f[A]

{{3*x11 + 2*(x11^2 + x12*x21) + 2, 
   3*x12 + 2*(x11*x12 + x22*x12) + 2}, 
  {3*x21 + 2*(x11*x21 + x22*x21) + 2, 
   3*x22 + 2*(x22^2 + x12*x21) + 2}}

D[f[A],{Flatten[A]}]

{{{4*x11 + 3, 2*x21, 2*x12, 0}, 
   {2*x12, 2*(x11 + x22) + 3, 0, 2*x12}}, 
  {{2*x21, 0, 2*(x11 + x22) + 3, 2*x21}, 
   {0, 2*x21, 2*x12, 4*x22 + 3}}}


Bob Hanlon

> 
> From: "Hiho" <haifeng.gong at gmail.com>
To: mathgroup at smc.vnet.net
> Date: 2004/12/11 Sat AM 05:21:05 EST
> To: mathgroup at smc.vnet.net
> Subject: [mg52773] [mg52713] Matrix m x n
> 
> How to tell Mathematica symbol A is a real m x n matrix?
> I want to do this:
> Assume A is a matrix,
> f(A) is a matrix function,
> I want to calculate the partial derivative of each elemet of f(A) with
> respect to eacg element of A.
> 
> Thanks!!
> 
> 


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