simple command

Syntax

fix ID group-ID nufeb/growth/simple keyword value

ID = user-assigned name for the fix
group-ID = ID of the group atoms to apply the fix to
keyword = growth
```
growth value = growth rate
```

Examples

group bac type 1

fix f_simple bac nufeb/growth/simple growth 4e-4

Description

Perform exponential microbial growth (or decay) to the atoms defined in group-ID. The fix is called at each biological step (see run_style nufeb) to update atom attributes. The following forward Euler method is implemented to update the mass (m) of each atom in the group:

\[ \begin{align}\begin{aligned}m'= m + \mu \Delta t\\\hfill\end{aligned}\end{align} \]

where \(\mu\) is the growth rate of the atoms (growth). The new mass is then used to update other atom attributes. For a coccus-style atom, its diameter changes accordingly. For a bacillus-style atom, the update is along the length of the atom while the variations in its width (diameter) are negligible.