Hi Elsaid.
> When I don't use hoomd.group.type(), it gives me errors like :
>
> File "/home/elsaid/untitled4.py", line 28, in <module>
> nvt = hoomd.md.integrate.nvt (group = groupB, kT = 4.11433*(10**-24), tau = 1.0)
>
> File "/home/elsaid/anaconda3/lib/python3.8/site-packages/hoomd/md/integrate.py", line 221, in __init__
> thermo = hoomd.compute._get_unique_thermo(group=group);
>
> File "/home/elsaid/anaconda3/lib/python3.8/site-packages/hoomd/compute.py", line 282, in _get_unique_thermo
> res = thermo(group);
>
> File "/home/elsaid/anaconda3/lib/python3.8/site-packages/hoomd/compute.py", line 209, in __init__
> if
group.name != 'all':
>
> AttributeError: 'list' object has no attribute 'name'
This is because you have assigned a list to `groupB` in the code above `groupB = hoomd.group.type('B');`, and a list is an invalid argument type for `hoomd.md.integrate.nvt (group = ...)`
> I still cannot access type 'B'
What do you mean by "access"?
Last time, I thought you meant that you wanted to inspect the particle data for particles of type 'B', so I suggested some syntax for exploring the particle data structure. But then it seemed like you were trying to define the group to be passed to the integrator, so we suggested `hoomd.group.type()`.
At a quick glance, your script looks fine. Are you getting an error?
> hoomd.md.integrate.mode_standard (dt = 0.005)
> nvt = hoomd.md.integrate.nvt (group = groupB, kT = 4.11433*(10**-24), tau = 1.0)
Depending on your other basic units, this temperature may be approximately equal to absolute zero. Also, if you are using the single-precision build (default), the equations of motion may evaluate to zero change due to floating point precision issues.
It's generally a good idea to choose units in HOOMD such that important values are as close to 1 in magnitude as possible. More than three orders of magnitude above or below 1 for parameters can lead to precision problems (too much truncation error).
See also
https://hoomd-blue.readthedocs.io/en/stable/units.html
Best,
Eric