# Dih types error in ions adding steps in gromacs

**URL:** <https://gromacs.bioexcel.eu/t/dih-types-error-in-ions-adding-steps-in-gromacs/3914>\
**Category:** User discussions\
**Tags:** forcefield, mdp-parameters, grompp, mdrun, simulation-setup\
**Created:** [March 29, 2022, 5:39am UTC](https://gromacs.bioexcel.eu/t/dih-types-error-in-ions-adding-steps-in-gromacs/3914 "2022-03-29T05:39:27Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![Santosh456](https://avatars.discourse-cdn.com/v4/letter/s/a8b319/32.png) [@Santosh456](https://gromacs.bioexcel.eu/u/Santosh456)\
**Post date:** [March 29, 2022, 5:39am UTC](https://gromacs.bioexcel.eu/t/dih-types-error-in-ions-adding-steps-in-gromacs/3914/1 "2022-03-29T05:39:28Z")

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etting the LD random seed to 2097101926  
Generated 100032 of the 100128 non-bonded parameter combinations  
Generating 1-4 interactions: fudge = 1  
Generated 65937 of the 100128 1-4 parameter combinations

ERROR 1 [file unk.itp, line 600]:  
No default Proper Dih. types

ERROR 2 [file unk.itp, line 614]:  
No default Proper Dih. types

ERROR 3 [file unk.itp, line 634]:  
No default Proper Dih. types

ERROR 4 [file unk.itp, line 644]:  
No default Proper Dih. types

ERROR 5 [file unk.itp, line 652]:  
No default Proper Dih. types

Excluding 3 bonded neighbours molecule type ‘Protein\_chain\_A’  
Excluding 3 bonded neighbours molecule type ‘UNK’  
Excluding 2 bonded neighbours molecule type ‘SOL’

NOTE 2 [file topol.top, line 72404]:  
System has non-zero total charge: -3.000000  
Total charge should normally be an integer. See  
[GROMACS - Gromacs](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 2020.1-Ubuntu-2020.1-1  
Source file: src/gromacs/gmxpreprocess/grompp.cpp (line 1928)

Fatal error:  
There were 5 errors in input file(s)

For more information and tips for troubleshooting, please check the GROMACS  
website at [Errors - Gromacs](http://www.gromacs.org/Documentation/Errors)

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<div class="post-metadata">

**Author:** ![Santosh456](https://avatars.discourse-cdn.com/v4/letter/s/a8b319/32.png) [@Santosh456](https://gromacs.bioexcel.eu/u/Santosh456)\
**Post date:** [March 29, 2022, 5:39am UTC](https://gromacs.bioexcel.eu/t/dih-types-error-in-ions-adding-steps-in-gromacs/3914/2 "2022-03-29T05:39:59Z")

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How to solve this issues

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<div class="post-metadata">

**Author:** ![alevilla](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/alevilla/32/439_2.png) [@alevilla](https://gromacs.bioexcel.eu/u/alevilla)\
**Post date:** [April 2, 2022, 10:59am UTC](https://gromacs.bioexcel.eu/t/dih-types-error-in-ions-adding-steps-in-gromacs/3914/3 "2022-04-02T10:59:48Z")

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Hi,  
I guess the problem is that dihedral angles are defined directive [dihedral] in the itp file, but pdb2gmx can not find information on the corresponding potential function and parameters, neither in the topology file nor force field files.  
\Alessandra

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<div class="post-metadata">

**Author:** ![Santosh456](https://avatars.discourse-cdn.com/v4/letter/s/a8b319/32.png) [@Santosh456](https://gromacs.bioexcel.eu/u/Santosh456)\
**Post date:** [April 2, 2022, 11:20am UTC](https://gromacs.bioexcel.eu/t/dih-types-error-in-ions-adding-steps-in-gromacs/3914/4 "2022-04-02T11:20:44Z")

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Thank You