Re: Telling Mathematica that a symbol is going to be a List?
- To: mathgroup at smc.vnet.net
- Subject: [mg50831] Re: [mg50817] Telling Mathematica that a symbol is going to be a List?
- From: "Maxim A. Dubinnyi" <maxim at nmr.ru>
- Date: Thu, 23 Sep 2004 05:27:12 -0400 (EDT)
- References: <200409220411.AAA18738@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Use definition
m[d_List]:={ { d[[1]], 0, 0}, {0, d[[2]], 0}, {0, 0, d[[3]]}
and then call
m[{d1,d2,d4}]
without any errors.
AES/newspost wrote:
>I want to define a function containing parameters that are going to be
>elements in a list, e.g. something like
>
> m := { { d[[1]], 0, 0}, {0, d[[2]], 0}, {0, 0, d[[3]]}
>
>but not define the list of values of d until later (and not put the
>parameters in as explicit arguments of m just to keep the appearance
>less cluttered and typing easier).
>
>If I then give an input line
>
> m /. {d -> {d1, d2, d3} } // MatrixForm
>
>I get "Part::partd" errors -- but the matrix then displays correctly.
>
>I can of course just Off[] the errors -- but is there a better way.
>
>
>
- References:
- Telling Mathematica that a symbol is going to be a List?
- From: AES/newspost <siegman@stanford.edu>
- Telling Mathematica that a symbol is going to be a List?