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1

we are trying to energy minimization with bond constraints. please find attached our data file and the input file for the minimization run. we looked into the ‘fix’ commands associated with the minimization run, but couldn’t find any to fox the carbon-hydrogen bonds between the individual atoms.

any help would be appreciated.

Granite Tait

in.minimization (351 Bytes)

data.open (9.69 KB)

2

please be a bit more mindful when posting to the mailing list:

  • use a meaningful subject line (having a descriptive subject massively increases your chances that somebody that could help you will read your e-mail)
  • always state what version of LAMMPS you are using.
  • be more descriptive in your explanation of what your problem is and explain what you have tried and what and why things have not worked the way you expected it.
  • formulate clear questions of what you want to be helped with or how. saying, “i could not figure it out, here is my input” is a bad way to ask for help. it gives the impression that you don’t even care enough to spend the time and effort to ask a proper question.

please keep in mind, that compared to the number of subscribers, the number of people that respond to requests on mailing lists is small, and if you don’t make it easy to determine what the problem is and how it can be solved (i.e. like in your case essentially ask the person responding to first figure out the question), then your chances to get any help quickly drop to something very close to zero.

in short: good and detailed questions -> good answers; bad and vague questions -> no help.

thanks for your understanding,
axel.

3

See the minimize doc page Restrictions section. There is no support in LAMMPS for performing minimizations

with fixed bond lengths (e.g. shake, rigid). However using stifff bonds is a reasonable approximation.

Steve