Re: Re: Animate Command and Vector Reference
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- Subject: [mg131439] Re: Re: Animate Command and Vector Reference
- From: Bob Hanlon <hanlonr357 at gmail.com>
- Date: Sat, 6 Jul 2013 05:03:46 -0400 (EDT)
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The argument of the function isn't defined until it is called, so a call
within Animate puts the argument within the Animate's scope.
sub[a_] := {{a, 1}, {a^2, 1}};
Animate[Graphics[{Line[{{0, 0}, sub[a][[1]]}]}], {a, -1, 1}]
Bob Hanlon
On Fri, Jul 5, 2013 at 3:05 AM, Alexei Boulbitch <Alexei.Boulbitch at iee.lu>wrote:
> This is a scoping issue. The a used in the Animate iterator is local to the
> Animate.
>
>
> sub = {{a, 1}, {a^2, 1}};
>
>
> OK, Bob, and why this
>
> sub[a_]:={{a,1},{a^2,1}};
>
>
> Animate[Graphics[{Line[{{0,0},sub[a][[1]]/.a->aa}]}],{{aa,-1,"a"},-1,1}]
>
> In version 6 this worked perfectly. What happened since?
>
> Best regards, Alexei
>
>
>
> This is a scoping issue. The a used in the Animate iterator is local to the
> Animate.
>
>
> sub = {{a, 1}, {a^2, 1}};
>
>
> Animate[
> Graphics[{
> Line[{{0, 0}, sub[[1]] /. a -> aa}]
> }],
> {{aa, -1, "a"}, -1, 1}]
>
>
>
> Bob Hanlon
>
> On Wed, Jul 3, 2013 at 4:59 AM, William Dickinson <
> william.dickinson.0718 at gmail.com> wrote:
>
> > I'm new to Mathematica and I want to create some animations. I tried
> > something like this:
> >
> > sub = {{a, 1}, {a^2, 1}}
> > Animate[Graphics[{Line[{{0, 0}, sub[[1]]}]}], {a, -1, 1}]
> >
> > and Mathematica give me an error. This error ( Coordinate {a, 1} should
> be
> > a pair of numbers, or a Scaled or Offset form.) is not helpful.
> >
> > I know that I can fix this by changing sub[[1]] to {a,1}, but this is not
> > a great solution. I have several places in the actual Animate command
> that
> > use sub[[1]] (some in conjunction with a Table command) and it would be
> > painful to do all of the replacing and rewriting. How can I make
> something
> > like this work?
> >
> > I suspect that I'm missing something simple....
> >
> >
> > Thanks in advance!
> >
> > Will
> >
> >
> >
>
> Alexei BOULBITCH, Dr., habil.
> IEE S.A.
> ZAE Weiergewan,
> 11, rue Edmond Reuter,
> L-5326 Contern, LUXEMBOURG
>
> Office phone : +352-2454-2566
> Office fax: +352-2454-3566
> mobile phone: +49 151 52 40 66 44
>
> e-mail: alexei.boulbitch at iee.lu
>
>
>
>