# How to solve No default Improper Dih. types

**URL:** <https://gromacs.bioexcel.eu/t/how-to-solve-no-default-improper-dih-types/6675>\
**Category:** User discussions\
**Tags:** grompp\
**Created:** [June 23, 2023, 1:00pm UTC](https://gromacs.bioexcel.eu/t/how-to-solve-no-default-improper-dih-types/6675 "2023-06-23T13:00:35Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![muhanad](https://avatars.discourse-cdn.com/v4/letter/m/77aa72/32.png) [@muhanad](https://gromacs.bioexcel.eu/u/muhanad)\
**Post date:** [June 23, 2023, 1:00pm UTC](https://gromacs.bioexcel.eu/t/how-to-solve-no-default-improper-dih-types/6675/1 "2023-06-23T13:00:35Z")

</div>

GROMACS version:2023.1  
GROMACS modification: Yes/No  
Here post your question  
I am using gromacs to run a simulation for glibenclamide as a ligand and ATP-sensitive potassium channel protein, however i am keep getting the error due to No default Improper Dih. types  
how I can solve the issue?  
below is the command the output message  
gmx grompp -f ions.mdp -c box\_sol.gro -p topol.top -o ION.tpr  
:-) GROMACS - gmx grompp, 2023.1 (-:

Executable: /usr/local/gromacs/bin/gmx  
Data prefix: /usr/local/gromacs  
Working dir: /home/muhanad/MD/glibenclamide-ATP sensitive potassium channel  
Command line:  
gmx grompp -f ions.mdp -c box\_sol.gro -p topol.top -o ION.tpr

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 -680659265

Generated 174825 of the 174936 non-bonded parameter combinations  
Generating 1-4 interactions: fudge = 1

Generated 124435 of the 174936 1-4 parameter combinations

ERROR 1 [file topol.top, line 169366]:  
No default Improper Dih. types

ERROR 2 [file topol.top, line 170184]:  
No default Improper Dih. types

Excluding 3 bonded neighbours molecule type ‘Protein\_chain\_A’

Excluding 3 bonded neighbours molecule type ‘LIG’

Excluding 2 bonded neighbours molecule type ‘SOL’

NOTE 2 [file topol.top, line 171983]:  
System has non-zero total charge: 25.000000 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.

There were 2 NOTEs

* * *

Program: gmx grompp, version 2023.1  
Source file: src/gromacs/gmxpreprocess/grompp.cpp (line 2198)

Fatal error:  
There were 2 errors in input file(s)

For more information and tips for troubleshooting, please check the GROMACS  
website at [Common Errors — GROMACS webpage https://www.gromacs.org documentation](http://www.gromacs.org/Documentation/Errors)