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Re: Interaction of Remove and Global variables in a Module

  • To: mathgroup at smc.vnet.net
  • Subject: [mg120210] Re: Interaction of Remove and Global variables in a Module
  • From: Bill Rowe <readnews at sbcglobal.net>
  • Date: Wed, 13 Jul 2011 03:11:23 -0400 (EDT)

On 7/12/11 at 6:59 AM, gianluca.gorni at uniud.it (Gianluca Gorni)
wrote:

>Suppose now that I do it more traditional-looking:

>Subscript[a, 0] = 1; Subscript[a, n_] :=
>Subscript[a, n] = 2 Subscript[a, n - 1];

>If I call Subscript[a, 2], its value will be remembered. What can I
>do to clear the values? Clear[a] and ClearAll[a] do not work.
>Remove[a] does work.

>Is there a better alternative?

If you want to use subscripted variables in the same manner as
normal variables (symbols) in Mathematica, then load the
Notation package and use Symbolize. Then they will behave as
symbols. If you choose not to use the Notation package you will
run into difficulties at times because something with Head
Subsecript simply isn't a Symbol and will not behave in all
respects like a Symbol.

For me, the effort to created subscripted variables that behave
like normal variables in Mathematica is much more effort than it
is worth. The only reason I ever use subscripted variables in
Mathematica is when I want the output to look like traditional
type set math you might find in a text and my intended audience
is colleagues which do not have Mathematica or are otherwise
unfamiliar with Mathematica. In these cases, what I will be
sending my colleagues is a static PDF file. So, I can evaluate
things using unsubscripted variables and edit them later so they
appear as having been done with subscripted variables. And if I
was sending something to a colleague who had Mathematica and was
familiar with it, I would send him the Mathematica notebook and
would not use subscripted variables.



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