# Gmx energy giving infinite potential, gmx analyze gives normal values

**URL:** <https://gromacs.bioexcel.eu/t/gmx-energy-giving-infinite-potential-gmx-analyze-gives-normal-values/9620>\
**Category:** User discussions\
**Tags:** analysis-tools\
**Created:** [July 11, 2024, 11:36am UTC](https://gromacs.bioexcel.eu/t/gmx-energy-giving-infinite-potential-gmx-analyze-gives-normal-values/9620 "2024-07-11T11:36:44Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![lisabere](https://avatars.discourse-cdn.com/v4/letter/l/ccd318/32.png) [@lisabere](https://gromacs.bioexcel.eu/u/lisabere)\
**Post date:** [July 11, 2024, 11:36am UTC](https://gromacs.bioexcel.eu/t/gmx-energy-giving-infinite-potential-gmx-analyze-gives-normal-values/9620/1 "2024-07-11T11:36:44Z")

</div>

GROMACS version: 2022.4-plumed\_2.8.1-dev  
GROMACS modification: No

Hello everyone,  
I used gmx energy -f md.edr to extract potential, and some other data, and obtained unreasonably large averages for some of the quantities:

```auto
Last energy frame read 375047 time 3750470.000         

Statistics over 937617501 steps [0.0000 through 3750470.0000 ps], 10 data sets
All statistics are over 9376176 points

Energy Average Err.Est. RMSD Tot-Drift
-------------------------------------------------------------------------------
Angle 63145.9 58 431.04 -281.358 (kJ/mol)
Proper Dih. -866685 17 268.573 -7.79246 (kJ/mol)
Potential -2.45376e+30 2.5e+30 inf -2.11104e+30 (kJ/mol)
Kinetic En. 367239 1 1080.63 5.92956 (kJ/mol)
Total Energy -2.45376e+30 2.5e+30 inf -2.11104e+30 (kJ/mol)
Temperature 299.578 0.00082 0.881532 0.00483695 (K)
Pres-XX -6.45462e+26 6.5e+26 inf -5.55565e+26 (bar)
Pres-YY -1.11853e+21 1.1e+21 inf -9.31533e+20 (bar)
Pres-ZZ -4.43904e+19 4.4e+19 inf -3.80858e+19 (bar)
#Surf*SurfTen 1.37214e+28 1.4e+28 inf 1.18104e+28 (bar nm)

```

Using python script or gmx analyze on energy.xvg file produced from this command gives adequate averages:

```auto
Read 10 sets of 375048 points, dt = 10

                                      std. dev. relative deviation of
                       standard --------- cumulants from those of
set average deviation sqrt(n-1) a Gaussian distribition
                                                      cum. 3 cum. 4
SS1 6.314611e+04 4.308130e+02 7.034706e-01 0.170 0.269
SS2 -8.666846e+05 2.688622e+02 4.390226e-01 0.002 0.002
SS3 -4.056204e+06 9.326106e+04 1.522851e+02 64.452 4011.803
SS4 3.672377e+05 1.079467e+03 1.762651e+00 0.006 0.000
SS5 -3.688966e+06 9.327248e+04 1.523038e+02 64.428 4009.618
SS6 2.995767e+02 8.805824e-01 1.437895e-03 0.006 0.000
SS7 -5.755222e+00 1.031434e+03 1.684219e+00 -62.889 3923.191
SS8 -5.465815e+00 1.031642e+03 1.684559e+00 -62.903 3925.295
SS9 -6.994908e+00 1.030962e+03 1.683448e+00 -62.900 3926.153
SS10 -5.885941e+01 6.701908e+03 1.094348e+01 0.002 0.000

```

I noticed that this happens if some of the values exceed 1e7 in a time step (which probably is not great but very far from 1e30 given by gmx energy). I am not sure why I have such ‘jumps’ of potential for some frames (I did check topology and it seems correct).

I would like to understand if this averages are what to be expected and which averages I should trust : gmx energy or gmx analyze

I can provide the corresponding .edr file if needed.  
Thank you for any information on this