Energy is passed correctly

It is common practise to use the potential energy as a collective energy. Some MD codes thus pass the potential energy to PLUMED. To check that this quantity has been passed correctly we can output the passed energy from PLUMED using the following input.

Click on the labels of the actions for more information on what each action computes
tested on2.10
tested onmaster
e: ENERGYCalculate the total potential energy of the simulation box. More details 
PRINTPrint quantities to a file. More details ARGthe labels of the values that you would like to print to the file=e FILEthe name of the file on which to output these quantities=colvar

We can then also output the energy from the MD code and check this matches the value output by PLUMED. We run a short trajectory to test that the energy is passed correctly.

Trajectory

Input and output files for the test calculation are available inthis zip archive

Results

MD code output PLUMED output Tolerance % Difference
-18174.695312 0.0 0.001 1817469531.1999998
-18171.693359 0.0 0.001 1817169335.9
-18191.779297 0.0 0.001 1819177929.7000003
-18159.357422 0.0 0.001 1815935742.2000003
-18140.072266 0.0 0.001 1814007226.6
-18115.982422 0.0 0.001 1811598242.2000003
-18094.060547 0.0 0.001 1809406054.7000003
-18080.794922 0.0 0.001 1808079492.2000003
-18079.359375 0.0 0.001 1807935937.5
-18088.0 0.0 0.001 1808800000.0
-18101.076172 0.0 0.001 1810107617.2000003
-18112.347656 0.0 0.001 1811234765.6000004
-18119.001953 0.0 0.001 1811900195.2999997
-18123.662109 0.0 0.001 1812366210.9
-18132.628906 0.0 0.001 1813262890.6000004
-18149.910156 0.0 0.001 1814991015.6000004
-18172.902344 0.0 0.001 1817290234.3999996
-18192.8125 0.0 0.001 1819281250.0
-18200.505859 0.0 0.001 1820050585.9
-18192.361328 0.0 0.001 1819236132.7999997

The table below includes some of the results from the calculation. The columns contain:

  1. The energies that were obtained from the MD code, $x_{md}$.
  2. The energies that were obtained from PLUMED, $x_{pl}$.
  3. The tolerances that were used when comparing these quantities, $\delta$.
  4. The values of $100\frac{\vert x_{md} - x_{pl}\vert }{ \delta }$.

If the PLUMED interface is working correctly the first two sets of numbers should be identical and the final column should be filled with zeros.

Graphical representation (beta)

A visualization of the table above:
energy_v2.10