show/hide this revision's text 4 Update with new Cantarella paper.

I suspect what you are seeking is not known. One of the experts in this area is Jason Cantarella, who coauthored (with R. Kusner and J. Sullivan) one of the definitive papers on this topic, "On the minimum ropelength of knots and links," Inventiones Mathematicae, Volume 150, Number 2, 257-286, 2002; Springer link). Jason has developed software that he calls RidgeRunner which implements a rope-length minimization, knot-tightening procedure. (I cannot speak to the details of his software, in particular, I don't know if it is "akin to simulated annealing.") He maintains a wonderful web page with (Quicktime) movies of his minimizer approaching what you call the "ideal knot" for many (more than 100!) knots and links. Here, for example, is the endpoint of his optimizer for $8_5$:
           8_5
Update. See the just-released paper, "The Shapes of Tight Composite Knots," arXiv:1110.3262 (math.DG), by Jason Cantarella and Al LaPointe and Eric Rawdon, for a description of the RidgeRunner software mentioned above. It "proceeds by constrained gradient descent," and "is designed to stop at local minima of the ropelength function." They reduce the probability of "false local minima" with several strategies. Their dataset now contains almost 1000 knots and links.

show/hide this revision's text 3 added 1 characters in body

I suspect what you are seeking is not known. One of the experts in this area is Jason Cantarella, who coauthored (with R. Kusner and J. Sullivan) one of the definitive papers in on this areatopic, "On the minimum ropelength of knots and links," Inventiones Mathematicae, Volume 150, Number 2, 257-286, 2002; Springer link). Jason has developed software that he calls RidgeRunner which implements a rope-length minimization, knot-tightening procedure. (I cannot speak to the details of his software, in particular, I don't know if it is "akin to simulated annealing.") He maintains a wonderful web page with (Quicktime) movies of his minimizer approaching what you call the "ideal knot" for many (more than 100!) knots and links. Here, for example, is the endpoint of his optimizer for $8_5$:
           8_5

show/hide this revision's text 2 added 18 characters in body

I suspect what you are seeking is not known. One of the experts in this area is Jason Cantarella, who coauthored (with R. Kusner and J. Sullivan) one of the definitive papers in this area, "On the minimum ropelength of knots and links," Inventiones Mathematicae, Volume 150, Number 2, 257-286, 2002; Springer link). Jason has developed software that he calls RidgeRunner which implements a rope-length minimization, knot-tightening procedure. (I cannot speak to the details of his software, in particular, I don't know if it is "akin to simulated annealing.") He maintains a wonderful web page with (Quicktime) movies of his minimizer approaching what you call the "ideal knot" for many (more than 100!) knots and links. Here, for example, is the endpoint of his optimizer for $8_5$:
           8_5

show/hide this revision's text 1