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Slow/jerky animations inside manipulate (more details)

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  • Subject: [mg100635] Slow/jerky animations inside manipulate (more details)
  • From: Porscha Louise McRobbie <pmcrobbi at>
  • Date: Wed, 10 Jun 2009 05:31:54 -0400 (EDT)

As several people have kindly pointed out, my first post was a bit too 
vague (my first time with Mathgroup). I am adding more specific 
details here. Thanks!

------Original post: "Slow/jerky animations inside manipulate" ---------
I have an Animate command (I'm using GraphicsRow to show two 
side-by-side synchronized animations) inside of Manipulate. The 
resulting animations play very fast and are jerky. I can adjust the 
play speed using AnimationRate, but  it must be slowed down by a 
ridiculous amount in order to look smooth. I've tried adjusting the 
RefreshRate, as wellas making time a slider variable and animating 
from within the Manipulate control panel,both with little success.
How can I create smooth animations, appropriate for class demonstrations?

-----Additional Comments-------------------------------------------------
My plots are actually simple. I am, however, solving an ODE inside of the
Manipulate/Animate commands. I've played around with the NDSolve 
options thinking it might make things faster, but again no success. 
Basically I just want two sliders to choose initial conditions for the 
ODEs, then animate the results.

Inside Manipulate, I solve the following ODEs, where the initial 
conditions q0,p0 are the slider variables:

sols = First@NDSolve[{q'[t] == p[t], p'[t] == 2 A De (Exp[-2 A (q[t] - xe)] -
          Exp[-A (q[t] - xe)]), q[0] == q0, p[0] == p0}, {q, p}, {t,0, 100}];

Inside Animate, I have two plots (tp is the animation variable):

1.  Plot solution q(tp) vs. tp, as well as a circle that moves along 
as the curve is being traced out:

p1 = Graphics[{ Point[{tp, Evaluate[q[tp] /. sols]}]}];
p2 = Quiet@Plot[Evaluate[q[T1] /. sols], {T1, 0, tp}, 
FIRSTplot = Show[p1, p2];

2. Plot a static background curve "Staticplot" (computed outside 
Animate), with a circle moving on it. The equation for the background 
curve is:

f(q)=De(1+Exp[-2 A (q-xe)]-2 Exp[-A (q-xe)])

The coordinates for Point below are {q,f(q)}.

p7 = Graphics[{Point[{Evaluate[q[tp] /. sols],
       De (1 + Exp[-2 A (Evaluate[q[tp] /. sols] - xe)] -
          2 Exp[-A (Evaluate[q[tp] /. sols] - xe)]) }]  }];
Thanks again for any help.

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