# Error of "There is no domain decomposition for 1 Ranks"?

**URL:** <https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402>\
**Category:** User discussions\
**Created:** [October 23, 2024, 8:26am UTC](https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402 "2024-10-23T08:26:48Z")\
**Posts on this page:** 5\
**Page:** 1

<div class="post-metadata">

**Author:** ![mj.rezayani](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/mj.rezayani/32/3918_2.png) [@mj.rezayani](https://gromacs.bioexcel.eu/u/mj.rezayani)\
**Post date:** [October 23, 2024, 8:26am UTC](https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402/1 "2024-10-23T08:26:48Z")

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GROMACS version: 2022 and 2024

Dear Gromacs users:

I want to energy minimize a structure in Gromacs. When I run the simulation using `mdrun` option.

```auto
gmx grompp -f minim.mdp -c box.gro -o min.tpr
gmx mdrun -deffnm min -v -nt 4 

```

I encounter with this error:

```auto
Fatal error:
There is no domain decomposition for 1 ranks that is compatible with the
given box and a minimum cell size of 15.5337 nm.
Change the number of ranks or mdrun option -rdd or -dds
Look in the log file for details on the domain decomposition

```

It is so strange. Because when I perform the simulation of the same system in nvt:

```auto
gmx grompp -f nvt.mdp -c box.gro -o nvt.tpr
gmx mdrun -deffnm nvt -v -nt 4 

```

it proceeds without any error.

What is the main reason for that?

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<div class="post-metadata">

**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\
**Post date:** [October 23, 2024, 12:02pm UTC](https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402/2 "2024-10-23T12:02:06Z")

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That doesn’t sound right and looks like a bug. Can you see in the log file where the distance of 15.5337 nm comes from?

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<div class="post-metadata">

**Author:** ![mj.rezayani](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/mj.rezayani/32/3918_2.png) [@mj.rezayani](https://gromacs.bioexcel.eu/u/mj.rezayani)\
**Post date:** [November 22, 2024, 11:25am UTC](https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402/3 "2024-11-22T11:25:51Z")

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Dear Hess,

Sorry for my late reply. I have attached the min.log file here. Please search for 16.3125 nm in the log file.

Thanks alot

[min.log](https://gromacs.bioexcel.eu/uploads/short-url/abdFkqCEHExR9rghb1uQj48z5jB.log) (14.3 KB)

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<div class="post-metadata">

**Author:** ![hess](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/hess/32/416_2.png) [@hess](https://gromacs.bioexcel.eu/u/hess)\
**Post date:** [November 22, 2024, 4:00pm UTC](https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402/4 "2024-11-22T16:00:20Z")

</div>

The log file tells you what causes the issue:  
two-body bonded interactions: 14.830 nm, Exclusion, atoms 28661 28702  
multi-body bonded interactions: 14.830 nm, Angle, atoms 28661 28702  
Minimum cell size due to bonded interactions: 16.312 nm

I guess you did something wrong in the setup of the initial coordinates which made bonded atoms separate by nearly 15 nm.

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<div class="post-metadata">

**Author:** ![mj.rezayani](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/mj.rezayani/32/3918_2.png) [@mj.rezayani](https://gromacs.bioexcel.eu/u/mj.rezayani)\
**Post date:** [November 22, 2024, 6:39pm UTC](https://gromacs.bioexcel.eu/t/error-of-there-is-no-domain-decomposition-for-1-ranks/10402/5 "2024-11-22T18:39:00Z")

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Dear,

Thank you for your help.