Hi all,
In my code, I am looking to compare system pe (potential energy) to a certain value every N timesteps. When pe approaches a certain value, I want to change the fix from an nvt to an npt ensemble. To do this, I use an if statement inside of run/every in order to change the fix. Below is the command that is currently included in my code:
fix 1 all nvt temp 50 50 0.1
thermo 100
dump 1 all atom 1000 dump.lj01
run 100000
run 100000 every 50 “variable p equal pe” &
“if ‘($p >=-19.3450) && ($p <=-19.3448)’ then ‘unfix 1’&‘fix 1 all npt temp 50 50 0.04283 iso 0.0 0.0 0.2’”
However, when I run my code, I get the following error: “Illegal unfix command”. I am not sure what the problem is here.
Any help would be much appreciated!
Zimu