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
-18192.574219 0.0 0.001 1819257421.8999996
-18161.835938 0.0 0.001 1816183593.8000002
-18144.712891 0.0 0.001 1814471289.1
-18122.765625 0.0 0.001 1812276562.5
-18102.484375 0.0 0.001 1810248437.5
-18090.230469 0.0 0.001 1809023046.8999996
-18089.066406 0.0 0.001 1808906640.6000004
-18097.527344 0.0 0.001 1809752734.3999996
-18110.205078 0.0 0.001 1811020507.7999997
-18121.09375 0.0 0.001 1812109375.0
-18127.490234 0.0 0.001 1812749023.4
-18132.197266 0.0 0.001 1813219726.6
-18141.261719 0.0 0.001 1814126171.8999996
-18158.695312 0.0 0.001 1815869531.1999998
-18181.683594 0.0 0.001 1818168359.3999996
-18201.503906 0.0 0.001 1820150390.6
-18209.072266 0.0 0.001 1820907226.6
-18200.759766 0.0 0.001 1820075976.6

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_master