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doc page clarifications

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This commit is contained in:
Steve Plimpton
2018-09-11 11:36:37 -06:00
parent a33f45f176
commit 983e8bb110
2 changed files with 13 additions and 6 deletions
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6
doc/src/fix_shake.txt
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@ -214,8 +214,10 @@ which can lead to poor energy conservation. You can test for this in
your system by running a constant NVE simulation with a particular set your system by running a constant NVE simulation with a particular set
of SHAKE parameters and monitoring the energy versus time. of SHAKE parameters and monitoring the energy versus time.
SHAKE or RATTLE should not be used to constrain an angle at 180 degrees SHAKE or RATTLE should not be used to constrain an angle at 180
(e.g. linear CO2 molecule). This causes numeric difficulties. degrees (e.g. linear CO2 molecule). This causes numeric difficulties.
You can use "fix rigid or fix rigid/small"_fix_rigid.html instead to
make a linear molecule rigid.
[Related commands:] none [Related commands:] none

13
doc/src/minimize.txt
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@ -216,10 +216,10 @@ The "fix box/relax"_fix_box_relax.html command can be used to apply an
external pressure to the simulation box and allow it to shrink/expand external pressure to the simulation box and allow it to shrink/expand
during the minimization. during the minimization.
Only a few other fixes (typically those that apply force constraints) Only a few other fixes (typically those that add forces) are invoked
are invoked during minimization. See the doc pages for individual during minimization. See the doc pages for individual "fix"_fix.html
"fix"_fix.html commands to see which ones are relevant. Current commands to see which ones are relevant. Current examples of fixes
examples of fixes that can be used include: that can be used include:
"fix addforce"_fix_addforce.html "fix addforce"_fix_addforce.html
"fix addtorque"_fix_addtorque.html "fix addtorque"_fix_addtorque.html
@ -242,6 +242,11 @@ you MUST enable the "fix_modify"_fix_modify.html {energy} option for
that fix. The doc pages for individual "fix"_fix.html commands that fix. The doc pages for individual "fix"_fix.html commands
specify if this should be done. specify if this should be done.
NOTE: The minimizers in LAMMPS do not allow for bonds (or angles, etc)
to be held fixed while atom coordinates are being relaxed, e.g. via
"fix shake"_fix_shake.html or "fix rigid"_fix_rigid.html. See more
info in the Restrictions section below.
:line :line
[Restrictions:] [Restrictions:]