Re: Symbolic matrix manipulation

• To: mathgroup at smc.vnet.net
• Subject: [mg46863] Re: Symbolic matrix manipulation
• From: David Gunter <spam at davidgunter.com>
• Date: Fri, 12 Mar 2004 02:02:47 -0500 (EST)
• References: <c238jv\$ii5\$1@smc.vnet.net> <c29888\$52u\$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

```Does anyone have an answer to this that doesn't require access to a
journal for which I have no subscription?

Thanks,
david

Paul Abbott wrote:

> In article <c238jv\$ii5\$1 at smc.vnet.net>, junk4 at microserf.org.uk (C Rose)
> wrote:
>
>
>>I'd like to know how one can perform symbolic matrix-vector
>>manipulations in Mathematica, without having to specify the contents
>>of the matrices or vectors.
>>
>>For example, imagine I have a vector-valued function
>>
>>f(x) = x^T A
>>
>>where A is a m x n matrix, x is an m-vector, and ^T indicates
>>transposition
>>
>>How can I differentiate f(x)---or perform other symbolic operations
>>using matrices or vectors---such that I get the result in terms of A
>>and x (i.e. I don't want to have to specify that
>>A={{a11, a12, a13}, {a21, a22, a23}, {a31, a32, a33}} or whatever).
>>
>>So, in the example above, I want Mathematica to tell me the answer is
>>
>>d/dx (f) = A
>>
>
>
> See The Mathematica Journal 8(4) (2002): 529-531
>
> Cheers,
> Paul
>

--
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```

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