Re: BracketingBar for output
- To: mathgroup at smc.vnet.net
- Subject: [mg15812] Re: BracketingBar for output
- From: Paul Abbott <paul at physics.uwa.edu.au>
- Date: Mon, 8 Feb 1999 03:25:39 -0500 (EST)
- Organization: University of Western Australia
- References: <79e86b$96l@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Peter Breitfeld wrote:
> In my "personal package" I have the function Betrag[x_]:=Sqrt[x.x]
>
> Now I want that in cases where this function can't be evaluated, the
> output in StandardForm is displayes as |x|. (left and right
> BracketingBar, these symbols you get when entering `ESC l| ESC' and
> `ESC r| ESC'.
Actually, to indicate such a norm I would use DoubleBracketingBar
instead of BracketingBar:
In[1]:= DoubleBracketingBar[(x_)?VectorQ]:= Sqrt[x . x]
In[2]:= DoubleBracketingBar[{a,b,c}] Out[2]=
2 2 2
Sqrt[a + b + c ]
Then there is no need to define Betrag.
Here are these input lines in TraditionalForm -- which is much more
readable:
Notebook[{
Cell[BoxData[
\(TraditionalForm
\`\[LeftDoubleBracketingBar]x_?VectorQ\[RightDoubleBracketingBar] :=
\ at \(x . x\)\)], "Input"],
Cell[CellGroupData[{
Cell[BoxData[
\(TraditionalForm
\`\[LeftDoubleBracketingBar]{a, b, c}\[RightDoubleBracketingBar]\)],
"Input"],
Cell[BoxData[
\(TraditionalForm\`\ at \(a\^2 + b\^2 + c\^2\)\)], "Output"] }, Open
]],
Cell[CellGroupData[{
Cell[BoxData[
\(TraditionalForm
\`\[LeftDoubleBracketingBar]x\[RightDoubleBracketingBar]\)],
"Input"],
Cell[BoxData[
\(TraditionalForm
\`\[LeftDoubleBracketingBar]x\[RightDoubleBracketingBar]\)],
"Output"]
}, Open ]]
}
]
Cheers,
Paul
____________________________________________________________________
Paul Abbott Phone: +61-8-9380-2734
Department of Physics Fax: +61-8-9380-1014
The University of Western Australia Nedlands WA 6907
mailto:paul at physics.uwa.edu.au AUSTRALIA
http://www.physics.uwa.edu.au/~paul
God IS a weakly left-handed dice player
____________________________________________________________________