struts - find self-contacts of tube with Geomview VECT core
struts -e <eps> -l <levels> -v <verbosity> <file>
struts is designed to demonstrate some of the features of
the liboctrope library. If the function d(x,y)
gives the space
distance between two points x and y on a polygonal curve
in 3-space, then struts finds local minima of d(x,y)
(excluding
distances in the form d(x,x)=0). The program records all locally
minimal pairs whose distance is within eps of the distance
of the closest such pair, and displays them in the Geomview SKEL
format. These locally minimal pairs are called ``struts''.
The user can fine-tune this tradeoff by setting levels. Setting levels = 1 reduces the algorithm to checking all pairs of edges (very slow), while for an n edge link the default is levels = 0.75*log2(n).
Find all nontrivial local minima of the self-distance function with length within 0.01 (the default) of minimum length for the file 3_1.vect:
struts 3_1.vect
Find nontrivial local minima with length within 0.0001 of minimum:
struts -e 0.0001 3_1.vect
the liboctrope manpage, the octrope_link manpage, http://www.geomview.org
Ted Ashton and Jason Cantarella
This program is covered by the GNU General Public License for free software, modified as follows: Any publication of computations performed using struts must include a citation of the paper A Fast Octree-Based Algorithm for Computing Ropelength (arXiv:math.DG/0409416).