This program demonstrates the minimization of the elastic energy of discrete elastic rod. Starting from the random configuration, the minimization make the rod return to the initial un-deformed configuration.
The 3x3 block sparse matrix data structure is defined such that it allows branching rods or coupling with other 3D deformation.
see also 622_FemRodStatic and 623_FemRodStatic.
This implementation of the discrete elastic rod is based on the following two papers.
"Discrete Viscous Threads"
Miklós Bergou, Basile Audoly, Etienne Vouga, Max Wardetzky, Eitan Grinspun
ACM Transactions on Graphics (SIGGRAPH) 2010
http://www.cs.columbia.edu/cg/threads/
"Efficient Yarn-based Cloth with Adaptive Contact Linearization"
Jonathan M. Kaldor, Doug L. James, Steve Marschner
ACM SIGGRAPH 2010
https://research.cs.cornell.edu/YarnCloth/