# 'No default U-B types', 'No default Proper Dih. types', 'System has non-zero total charge:10.000000'

**URL:** <https://gromacs.bioexcel.eu/t/no-default-u-b-types-no-default-proper-dih-types-system-has-non-zero-total-charge-10-000000/6934>\
**Category:** User discussions\
**Tags:** grompp\
**Created:** [July 31, 2023, 4:38pm UTC](https://gromacs.bioexcel.eu/t/no-default-u-b-types-no-default-proper-dih-types-system-has-non-zero-total-charge-10-000000/6934 "2023-07-31T16:38:54Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![teerna](https://avatars.discourse-cdn.com/v4/letter/t/a88e4f/32.png) [@teerna](https://gromacs.bioexcel.eu/u/teerna)\
**Post date:** [July 31, 2023, 4:38pm UTC](https://gromacs.bioexcel.eu/t/no-default-u-b-types-no-default-proper-dih-types-system-has-non-zero-total-charge-10-000000/6934/1 "2023-07-31T16:38:54Z")

</div>

GROMACS version: 2020.1  
GROMACS modification: No

**I am trying to set up a system that has a docked complex, the two molecules have been given the same chain ID and separated by a TER. Upon grompp, I get these errors:**  
Ignoring obsolete mdp entry ‘title’ Ignoring obsolete mdp entry ‘ns\_type’ NOTE 1 [file ions.mdp]: With Verlet lists the optimal nstlist is \>= 10, with GPUs \>= 20. Note that with the Verlet scheme, nstlist has no effect on the accuracy of your simulation. Setting the LD random seed to -1567179186 Generated 20503 of the 20503 non-bonded parameter combinations Generating 1-4 interactions: fudge = 1 Generated 17396 of the 20503 1-4 parameter combinations ERROR 1 [file topol\_Protein\_chain\_A.itp, line 57855]: No default U-B types ERROR 2 [file topol\_Protein\_chain\_A.itp, line 58381]: No default U-B types ERROR 3 [file topol\_Protein\_chain\_A.itp, line 58462]: No default U-B types ERROR 4 [file topol\_Protein\_chain\_A.itp, line 81335]: No default Proper Dih. types ERROR 5 [file topol\_Protein\_chain\_A.itp, line 81336]: No default Proper Dih. types ERROR 6 [file topol\_Protein\_chain\_A.itp, line 81337]: No default Proper Dih. types ERROR 7 [file topol\_Protein\_chain\_A.itp, line 81339]: No default Proper Dih. types ERROR 8 [file topol\_Protein\_chain\_A.itp, line 82122]: No default Proper Dih. types ERROR 9 [file topol\_Protein\_chain\_A.itp, line 82123]: No default Proper Dih. types Excluding 3 bonded neighbours molecule type ‘Protein\_chain\_A’ Excluding 3 bonded neighbours molecule type ‘Protein\_chain\_A2’ Excluding 2 bonded neighbours molecule type ‘SOL’ NOTE 2 [file topol.top, line 48]: System has non-zero total charge: 10.000000 Total charge should normally be an integer. See [Floating point arithmetic — GROMACS webpage https://www.gromacs.org documentation](http://www.gromacs.org/Documentation/Floating_Point_Arithmetic) for discussion on how close it should be to an integer.

**I have checked the .itp file, there no fractional charge, qtot is integral value. Also, I am not sure how to go about incorporating the parameters (‘No default U-B types’, ‘No default Proper Dih. types’)?**

**I am using the same ions.mdp file as this: [http://www.mdtutorials.com/gmx/complex/Files/ions.mdp](http://www.mdtutorials.com/gmx/complex/Files/ions.mdp)**

**Many thanks!**