Bug in Manipulate with Trigger control?
- To: mathgroup at smc.vnet.net
- Subject: [mg92750] Bug in Manipulate with Trigger control?
- From: "michael.p.croucher at googlemail.com" <michael.p.croucher at googlemail.com>
- Date: Sun, 12 Oct 2008 04:32:43 -0400 (EDT)
Hi all
I have been playing around with Manipulate a bit and am wondering
about the behavior of the code below
Manipulate[
theta = pointnum*2 Pi/128.;
x = r Cos[theta];
y = r Sin[theta];
Pointlist[[pointnum]] = Point[{x, y}];
Graphics[{PointSize[Large],
Point[{x, y}], {PointSize[Small], Pointlist}},
PlotRange -> {{-5, 5}, {-5, 5}}]
, {r, 2, 4}
, {pointnum, 1, 129, 1, ControlType -> Trigger,
DisplayAllSteps -> True, AnimationRepetitions -> 10}
, TrackedSymbols -> {pointnum, r},
Initialization :> {Pointlist = Table[{}, {129}]}
]
When the pointnum trigger is pressed a big point traces a circle and
leaves a trail of smaller points behind it. In my current setup
(6.0.0 on windows) the trail is sometimes incomplete despite the fact
that I have asked for DisplayAllSteps->True
The code above always seems to misses the 78th point on my machine.
Does anyone know what is going on?
Finally, AnimationRate doesn't work as expected. Putting
AnimationRate->64 should take 2 seconds for a complete circle but it
takes longer.
It's 2am so maybe I am just being dense and everything is behaving as
it should be...another pair of eyes would be greatly appreciated.
Cheers,
Mike