Search found 5 matches

by cpp6f
Fri Oct 02, 2009 9:41 pm
Forum: VTSTTools
Topic: Using the Jacobian instead of the Hessian for optimization
Replies: 1
Views: 31098

Using the Jacobian instead of the Hessian for optimization

Is there any particular reason why you haven't implemented something akin to Broyden's method that updates a non-symmetric Jacobian instead of a symmetric Hessian? This seems the logical thing to do since the forces are non-conservative. Is there a problem with this that I'm overlooking?

Craig
by cpp6f
Mon Feb 09, 2009 4:43 am
Forum: VTSTTools
Topic: major bug found in DNEB method
Replies: 2
Views: 40476

major bug found in DNEB method

I just noticed a bug in the dneb portion of neb.F

Line 244 reads:
f_dneb = f_spring_perp-vproj(f_spring_perp,f_perp)
This is the line that makes the dneb force normal to the real perpendicular force.
According to equation (14) of Sheppard et al. (2008), this equation should be:
f_dneb = f_spring ...
by cpp6f
Wed Mar 05, 2008 1:47 am
Forum: VTSTTools
Topic: error on website for dimer method
Replies: 3
Views: 48125

Re: error on website for dimer method

Based on the code in the subroutine Dimer_Step (pasted below), control will be passed to the optimizer without ever calling RotateDimer if FNr<FNMin. If this condition is not met, one CG step will be performed, and the condition FN1r<FNMax will determine whether control is passed to the optimizer or ...
by cpp6f
Sat Mar 01, 2008 5:09 am
Forum: VTSTTools
Topic: error on website for dimer method
Replies: 3
Views: 48125

error on website for dimer method

After looking at the source code for the dimer method, I noticed what I believe to be an error on the webpage http://theory.cm.utexas.edu/vtsttools/dimer/
At the bottom, where the input parameters are described, it looks like the descriptions of DFNMin an DFNMax are switched. DFNmin is the minimum ...
by cpp6f
Wed Oct 11, 2006 2:14 am
Forum: VTSTTools
Topic: downloading new optimizers
Replies: 1
Views: 32628

downloading new optimizers

How do I download the new optimizers? They aren't in the vtstcode.tar.gz file.