Re: Pattern matching partial derivatives
- To: mathgroup at smc.vnet.net
- Subject: [mg52409] Re: Pattern matching partial derivatives
- From: David Bailey <dave at Remove_Thisdbailey.co.uk>
- Date: Fri, 26 Nov 2004 01:04:39 -0500 (EST)
- References: <co4dsi$l82$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Nicolas Girard wrote:
> Hi all,
> I can't get finding patterns that would match a simple partial derivative:
>
> Input:
> ?f
> ?x
> D[f, x, NonConstants -> {f}] // FullForm
>
> Output:
> Global`f
> Global`x
> D[f, x, Rule[NonConstants, List[f]]]
>
> Input:
> MatchQ[
> D[f, x, Rule[NonConstants, List[f]]],
> D[f_, x_, Rule[NonConstants, nc_]]
> ]
> Output:
> False
>
>
> Am I damned ?
> Many thanks in advance !
> Cheers,
> Nicolas
>
Nicolas,
Yes, getting this output from Mathematica can be a sign of damnation!
Alternatively, look at this:
D[f_, x_, Rule[NonConstants, nc_]] // FullForm
0
If you want to manipulate derivatives in complicated ways, one way is to
use your own notation for a derivative (say dD) which will obviously not
evaluate, and then use dD ->D to get evaluation when you need it.
David