A parallel run should not arrive here without DD support

User discussions
1

GROMACS version:2022.3
GROMACS modification: Yes/No

Hi,

I want to calculate chemical potential of CH4 in a box with 2 polymer chains (3000 atoms) using test particle insertion method. After the following command:

gmx mdrun -s tpi.tpr -o tpi.trr -x tpi.xtc -c box1.gro -e tpi.edr -g tpi.log -rerun box0.xtc

I am facing the error:

Assertion failed:
Condition: !PAR(cr) || canUseDomainDecomposition

A parallel run should not arrive here without DD support

I would greatly appreciate any advice to solve the problem.

2

Hi!

It looks like GROMACS tries to automatically choose the multi-rank mode, which is not compatible with TPI. Can you try adding -ntmpi 1 to your gmx mdrun command line to manually force the compliant config?

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3

Thank you! It works.

4

Glad that it worked for you!

We’ll try to fix it properly in GROMACS 2023.2.

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5

Note that TPI with MPI parallelization actually should work, but this has been broken since the 2021 release.

The same issue is present for normal mode analysis.

I pushed up a fix which should hopefully make it into 2023.1:

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