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Re: symbolic matrix calculation doesn't work

  • To: mathgroup at smc.vnet.net
  • Subject: [mg56384] Re: [mg56368] symbolic matrix calculation doesn't work
  • From: DrBob <drbob at bigfoot.com>
  • Date: Sat, 23 Apr 2005 01:16:16 -0400 (EDT)
  • References: <200504221025.GAA18917@smc.vnet.net>
  • Reply-to: drbob at bigfoot.com
  • Sender: owner-wri-mathgroup at wolfram.com

Contrary to what it says in Help, MatrixForm isn't a wrapper.

You could input something like this:

MatrixForm[T = (-(2*u)^(-1))*{{1, 1}, {1, 1}}]
MatrixForm[d = {En1, In1}]
MatrixForm[P = {{0, 1}, {1, 0}}]
a = (1/2)*Inverse[P - T . P . Transpose[
         Conjugate[T]]] . d . Conjugate[d]

(output omitted)

Note that the line

Evaluate[a]

in your notebook could have been simply

a

There is no difference.

The result is a scalar, as you probably intended, but there's no way to simplify away the conjugates without assumptions about the variables. For instance,

Simplify[a, u > 0]

((En1 + In1*(-1 + 2*u^2))*
     Conjugate[En1] +
    (In1 + En1*(-1 + 2*u^2))*
     Conjugate[In1])/
   (4*(-1 + u^2))

Bobby

On Fri, 22 Apr 2005 06:25:51 -0400 (EDT), Jack <jack.peng at gmail.com> wrote:

> Hi,
>    I am new to Mathematica and I can't seem to get mathematica to
> multiply symbolic matrices. Can anyone please help? The notebook file
> is at http://www.eecs.berkeley.edu/~xpeng/question/
>    Thank you so much. Please reply to xpeng at eecs.berkeley.edu.
>
> Jack
>
>
>
>



-- 
DrBob at bigfoot.com


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