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MathGroup Archive 2005

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Re: D[...] change in 5.1

  • To: mathgroup at smc.vnet.net
  • Subject: [mg58697] Re: D[...] change in 5.1
  • From: Jean-Marc Gulliet <jeanmarc.gulliet at gmail.com>
  • Date: Fri, 15 Jul 2005 03:02:12 -0400 (EDT)
  • Organization: The Open University, Milton Keynes, England
  • References: <db57qa$4ri$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Alexei Akolzin wrote:
> Hi, 
> 
> In previous version two lines below seemed to work as intended:
> 
> In: 
> n /: D[n[i_], x[j_], NonConstants -> {n,r}] := (1/r)( d[i,j] - n[i] n[j] );
> D[ 1 + n[k], x[l] ]
> 
> Out: (-n[k] n[l] + d[k,l]) \ r
> 
> But now in ver 5.1 I get something like:
> Out: D[n, x[l], NonConstants -> {J, r, n}] (1)
> 
> The funny part is that D[ n[k], x[l] ] is recognized and substituted by the
> expression associated with definition of n.
> 
> I wonder whether there is a possibility to get Mathematica 5.1 recognize
> n[k] as an indexed symbol n.
> 
> Thanks.
> Alexei Akolzin.
> 
Hi Alexei,

Have you posted the correct expression? I am asking because here what I 
get with Mathematica 5.1.1:

In[1]:=
n /: D[n[i_], x[j_], NonConstants -> {n, r}] :=
     (1/r)*(d[i, j] - n[i]*n[j]);

In[2]:=
D[1 + n[k], x[l]]

Out[2]=
0

In[3]:=
Information["n", LongForm -> False]

n

n /: D[n[i_], x[j_], NonConstants -> {n, r}] :=
      (1/r)*(d[i, j] - n[i]*n[j])

In[4]:=
$Version

Out[4]=
"5.1 for Microsoft Windows (January 27, 2005)"

Best regards,
/J.M.


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