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Re: Re-virginating Manipulates?

  • To: mathgroup at
  • Subject: [mg114293] Re: Re-virginating Manipulates?
  • From: "Ingolf Dahl" <ingolf.dahl at>
  • Date: Tue, 30 Nov 2010 04:03:57 -0500 (EST)

This interaction between different Manipulate cells can be a pest,
especially in the authoring notebook for a new demonstration, where you
should have the same Manipulate cell in several variants, as thumbnail and
as snapshots. If you manipulate one of them, the other cells might interact,
especially if some variables are defined in the Initialization option. I
denote this problem "the Isolation Problem". The Manipulate command puts all
controls inside a DynamicModuleBox, (hopefully) isolating them from
interaction with other cells. However, variables defined by the
Initialization option are defined outside the DynamicModule, and they might
interfere with outside code and other Manipulate cells, if the same variable
names are reused. According to my current understanding, there are three
measures you could take: some combination of  them could be effective.
Please correct me if I am wrong, I would very much appreciate that.

1) One way to avoid interaction between Manipulate cells is of course to use
strictly different names in the different cells, maybe containing some
cell-specific string in such a way that it easily replaced.

2) Another method is to use an option CellContext, which might be set to
Cell for the whole notebook. Then, a unique default context is used for
every cells in the notebook. 
The CellContext option can be set by selecting Format -> Option Inspector ->
(Selected Notebook, by Category) -> Cell Options -> Evaluation Options ->
CellContext. It might alternatively be set by the command
SetOptions[EvaluationNotebook[ ], CellContext->Cell]. 
However, I am not sure that this always is effective to stop interaction
between the cells.

3) If we do Show Expression on the Manipulate cell (Shift+Ctrl+E in
Windows), we see that all variables are defined in the $CellContext`
context. Do Find&Replace and replace $CellContext` with something else, e.g.
CellContext01`. Close Show Expression and open the next Manipulate cell, and
replace in the same way with CellContext02`, and so on.

Measure 1 and 3 might break down if we then do "Update thumbnails and
snapshots" in a Demonstrations authoring notebook.

Best regards
Ingolf Dahl
ingolf.dahl at

> -----Original Message-----
> From: AES [mailto:siegman at]
> Sent: den 29 november 2010 12:07
> To: mathgroup at
> Subject: [mg114256] Re-virginating Manipulates?
> Let's define the label "virgin" for a Mathematica notebook as referring
> to the condition and content of a notebook file that's been opened for
> the first time, had some cells typed into it, maybe been Saved, but none
> of its cells have ever been executed.
> How can one re-virginate such a notebook (and also the currently
> running Mathematica app and kernel, if necessary) after any (or all) of
> the cells in this notebook have been executed one or more times --
> especially if the notebook contains one or more Manipulates?
> [If you want more detail, the objective is to code a number of
> (potentially multi-cell) "demos" -- call them demo_a, demo_b, ... --
> each of which contains a Manipulate, and all of which are totally
> independent of each other (no transfer of info between different demos
> needed or wanted); and then be able to jump around randomly amongst
> these demos, executing or re-executing them, and getting identical
> results each time a given demo is executed, regardless of what's
> happened before it is selected and executed.
> Each demo is, preferably, a separate notebook (a separate file),  or
> multiple demos could be cascaded in a single notebook, in the form
>       <<Header cell>>
>       demo_a
>       <<Header cell>>
>       demo_b
>       <<Header cell>>
>       demo_c
>       <<Header cell>>
> What initial cells does each demo_x need to make that demo execute as a
> virgin demo when jumped to?]

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