# Conserved En. with v-rescale thermostat drifts

**URL:** <https://gromacs.bioexcel.eu/t/conserved-en-with-v-rescale-thermostat-drifts/7093>\
**Category:** User discussions\
**Created:** [August 29, 2023, 1:24am UTC](https://gromacs.bioexcel.eu/t/conserved-en-with-v-rescale-thermostat-drifts/7093 "2023-08-29T01:24:15Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![istewart\_mit](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/istewart_mit/32/2920_2.png) [@istewart\_mit](https://gromacs.bioexcel.eu/u/istewart_mit)\
**Post date:** [August 29, 2023, 1:24am UTC](https://gromacs.bioexcel.eu/t/conserved-en-with-v-rescale-thermostat-drifts/7093/1 "2023-08-29T01:24:15Z")

</div>

GROMACS version: 2019.6  
GROMACS modification: No

After running NVT ensemble with v-rescale thermostat, I get a drift and my conserved energy decreases. I am wondering if someone can tell me whether or not this drift is too much? I see that total energy and potential energy are nicely flat.

I am attaching my job script, my log file, and a picture of my conserved energy.

When I run gmx energy -f ener.edr I get:  
Conserved En.  
6.57672e+07 1200 2492.56 -8513.98 (kJ/mol)

 ![cons](https://europe1.discourse-cdn.com/flex017/uploads/bioexcel1/original/2X/e/ec1981a2d9d939c082f62dc51635b570d94f90f9.png)

```auto
#!/bin/bash
#SBATCH --job-name="production run"
#SBATCH --partition=sched_mit_buehler
#SBATCH --constraint=centos7
#SBATCH --mem=50G
#SBATCH -N 20
#SBATCH --ntasks 640
#SBATCH --time=12:00:00
#SBATCH --output=output_prod.txt
#SBATCH --error=error_prod.txt
#SBATCH --mail-type=ALL
#SBATCH --mail-user=is1@wellesley.edu

echo
echo "============================ Messages from Goddess ============================"
echo " * Job starting from: "`date`
echo " * Job ID : "$SLURM_JOBID
echo " * Job name : "$SLURM_JOB_NAME
echo " * Working directory: "${SLURM_SUBMIT_DIR/$HOME/"~"}
echo "==============================================================================="
echo

module purge
#module load /home/istewart/gromacs/gromacs-2019.6
source ~/gromacs/2019.6/install/bin/GMXRC
source /home/istewart/plumed2-2.8.2/sourceme.sh
module load engaging/openmpi/2.0.3

gmx_mpi=/home/istewart/gromacs/2019.6/install/bin/gmx_mpi

if [-n "$SLURM_CPUS_PER_TASK"]; then
     ntomp="$SLURM_CPUS_PER_TASK"
else
     ntomp="1"
fi

# setting OMP_NUM_THREADS to the value used for ntomp to avoid complaints from gromacs
export OMP_NUM_THREADS=$ntomp

mpirun -np $SLURM_NTASKS $gmx_mpi mdrun -ntomp $ntomp -s 2019.tpr -v -o trajectory

echo "============================ Messages from Goddess ============================"
echo " * Job ended at : "`date`
echo "==============================================================================="
echo

```

[md (1).log](https://gromacs.bioexcel.eu/uploads/short-url/ixnOfx4TIZDXGwNqqNnph8Mjsl.log) (1.5 MB)

---

<div class="post-metadata">

**Author:** ![istewart\_mit](https://dub1.discourse-cdn.com/flex017/user_avatar/gromacs.bioexcel.eu/istewart_mit/32/2920_2.png) [@istewart\_mit](https://gromacs.bioexcel.eu/u/istewart_mit)\
**Post date:** [August 29, 2023, 1:27am UTC](https://gromacs.bioexcel.eu/t/conserved-en-with-v-rescale-thermostat-drifts/7093/2 "2023-08-29T01:27:14Z")

</div>

Additionally, here is the mdp for the NVT

Thanks!  
[eq1\_10.mdp](https://gromacs.bioexcel.eu/uploads/short-url/xuHS5vQhPh4AkWHcZJ0pYjimx7d.mdp) (4.2 KB)