Re: Defining N for a new entity
- To: mathgroup at smc.vnet.net
- Subject: [mg66775] Re: Defining N for a new entity
- From: Giuseppe Bilotta <bilotta78 at hotpop.com>
- Date: Tue, 30 May 2006 05:48:11 -0400 (EDT)
- References: <e5aucq$nn4$1@smc.vnet.net> <e5ehbc$7kt$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
On Mon, 29 May 2006 10:10:52 +0000 (UTC), Scout wrote: > "Giuseppe Bilotta" <bilotta78 at hotpop.com> > news:e5aucq$nn4$1 at smc.vnet.net... >> So I was looking for a way to tell Mathematica that applying N to an >> AffineExpression should only actually apply it to c and xi, something >> like >> >> N[AffineExpression[c_, dev_]] := >> AffineExpression[N[c], MapAt[N,#,{2}]&/@ dev] >> >> but if I actually do this and then call >> >> AffineExpression[1, {{1, 1}}] >> N[%] >> >> the Mathematica kernel (5.2.0.0) dies without any message. >> >> Does anybody have an idea of what could the reason be? And what could >> I do as a workaround? > > Hi Giuseppe, > have you already tried to define an upvalue for AffineExpression[] ? > Something like > N[AffineExpression[c_, dev_]] ^:= AffineExpression[....] > > For the other questions I don't know what's happening. > HTH, > ~Scout~ Sadly, the kernel dies regardless of whether I define it as an upvalue or not. The strange thing is that this is something related to the internals of N: MyN[AffineExpression[c_, dev_?MatrixQ]] ^:= AffineExpression[N[c], MapAt[N,#, 2] & /@ dev]; N[AffineExpression[c_, dev_?MatrixQ]] ^:= AffineExpression[N[c], MapAt[N, #, 2] & /@ dev]; AffineExpression[1/6, {{2, 1/3}}] MyN[%] N[%%] The strange thing is that the kernel dies without a message or anything. -- Giuseppe "Oblomov" Bilotta "I'm never quite so stupid as when I'm being smart" --Linus van Pelt