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Re: NDSolve Repeated convergence test failure

• To: mathgroup at smc.vnet.net
• Subject: [mg47135] Re: NDSolve Repeated convergence test failure
• From: Steven Rey Ortiz <sro7516 at cs.tamu.edu>
• Date: Sat, 27 Mar 2004 01:34:38 -0500 (EST)
• Organization: Texas A&M University, College Station, Texas
• References: <c3uem8$9ub$1@smc.vnet.net> <c40sv5$mrs$1@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Paul,

Thank you so much for your reply.  Reading your reply, I realized that I
can identify the singularity, and solve this problem in a two part
"piecewise" fashion.  It would still be nice if NDSolve identified this
transition from a second order to first order ODE and correctly integrated
the entire solution, but perhaps there are technical reasons that it
doesn't.  So, for now, I have an effective workaround in place.  Seeing
the complete plot, I also realized I had a mistake in the control law,
which I have corrected.  The updated notebook is available here in case
you are interested.

http://students.cs.tamu.edu/sro7516/double-pendulum-2.nb

Thank you!

Steve