Re: UpSetDelayed and N
- To: mathgroup at smc.vnet.net
- Subject: [mg57138] Re: [mg57128] UpSetDelayed and N
- From: Andrzej Kozlowski <akoz at mimuw.edu.pl>
- Date: Tue, 17 May 2005 01:20:01 -0400 (EDT)
- References: <200505170135.VAA23186@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On 17 May 2005, at 10:35, François Wirion wrote:
> Hello,
>
> I have done the following in Mathematica:
> P[N[x]] ^:= 0
> If I put in
> P[N[x]]
> it returns
> 0
> as expected.
>
> However, I haven't been able to find where this definition is stored.
> Calling the following for P
>
> OwnValues[P]
> DownValues[P]
> UpValues[P]
> SubValues[P]
> NValues[P]
> DefaultValues[P]
> FormatValues[P]
> Messages[P]
>
> and N
>
> OwnValues[N]
> DownValues[N]
> UpValues[N]
> SubValues[N]
> NValues[N]
> DefaultValues[N]
> FormatValues[N]
> Messages[N]
>
> returns mostly empty lists, but no definition that says that P[N[x]] is
> 0. Where then would this be stored?
>
> Thank you for any help or advice,
>
> François Wirion
It is stored as an Upvalue of x.
P[N[x]] ^:= 0
UpValues[x]
{HoldPattern[P(x)]:>0}
The reason is of course that N[x] returns x.
Andrzej Kozlowski
- References:
- UpSetDelayed and N
- From: "François Wirion" <muthaluva@gmail.com>
- UpSetDelayed and N