[Ifeffit] max number of restraints

Bruce Ravel bravel at anl.gov
Sat Apr 14 22:36:11 CDT 2007

On Friday 13 April 2007 19:08, Victor.Streltsov at csiro.au wrote:
> I am confused.
> I thought I did exactly what Bruce said. I added them in quadrature and
> used square root of that as the restraint in artemis:
> After summing in quadrature:
> restraint_sum = sqrt((restraint1)^2 + (restraint2)^2 +
> (restraint3)^2...)
> I asked artemis "to build restraint from "restraint_sum"" and
> artemis added line: res_restraint_sum=penalty(restraint_sum,n1,n2)*scale
> This way of summing them seems closer to the way of adding them
> individually squared to the "vector to be minimized", provided
> artemis/ifeffit squares them before appending to the "vector" (you don't
> need to square them before). I guess the questions is what artemis does
> when asked to "build restraint from ..."?

"penalty" is just a normal ifeffit function.  It is useful for making
restraints, but has no special relationship to restraints.  Use the
sum in quadrature as *the* restraint, not as an argument of the
penalty function.


 Bruce Ravel  ---------------------------------------------- bravel at anl.gov

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