See also

http://rosettacode.org/wiki/Animate_a_pendulum#J




On Fri, May 16, 2014 at 7:04 AM, Joe Bogner <[email protected]> wrote:

> Brian- neat... It can also be plotted with
>
> GA =: 9.80665 NB. Gravitational Acceleration (meters per second squared)
> NB. FORM = 'Time={:6.3f}, Angle={:6.3f}, Speed={:6.3f}'
>
> require 'plot'
> sin =: 1&o.
> pi =: 1p1
> main =: 3 : 0
>     pos=: 0 $ 0
>     length =: 9.0            NB. Of pendulum (meters)
>     ngol =: - GA % length    NB. Negative G over L
>     total_time =: 0.0        NB. Seconds
>     angle =: 1.0             NB. Initial angle of pendulum (radians)
>     speed =: 0.0             NB. Initial angular velocity (radians/second)
>     time_step =: 0.05        NB. Seconds
>     while. total_time < 30.0 do.
>       total_time =: total_time + time_step
>       speed =: speed + ngol * (sin angle) * time_step
>       angle =: angle + speed * time_step
>       smoutput 'setheading :',":angle + pi
>       pos=: pos,(angle + pi)
>   end.
>   plot pos
> )
>
> It looks like a reasonably correct path to me
>
>
> On Thu, May 15, 2014 at 1:46 PM, Joe Bogner <[email protected]> wrote:
>
> > On Thu, May 15, 2014 at 1:20 PM, Brian Schott <[email protected]
> >wrote:
> >
> >>
> >> I am not familiar with the dot() function used in the python
> >> version. Does anyone know what the dot() function does?
> >>
> >>
> > https://docs.python.org/2/library/turtle.html#turtle.dot
> >
> > "Draw a circular dot with diameter size, using color. If size is not
> > given, the maximum of pensize+4 and 2*pensize is used."
> >
> > I ran the python version fine. It draws a swinging pendulumn
> >
> ----------------------------------------------------------------------
> For information about J forums see http://www.jsoftware.com/forums.htm
>
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For information about J forums see http://www.jsoftware.com/forums.htm

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