October  6 2025   6:29:36.644 PM
 
md():
  Fortran90 version
  A molecular dynamics program.
 
  Enter ND, the spatial dimension (2 or 3 ):
 
  Enter NP, the number of particles (500, for instance):
 
  Enter STEP_NUM, the number of time steps (500, for instance):
 
  ND, the spatial dimension, is        3
  NP, the number of particles in the simulation is     1000
  STEP_NUM, the number of time steps, is      400
  DT, the size of each time step, is   0.100000E-03
 
  Initializing positions, velocities, and accelerations.
 
  Computing initial forces and energies.
 
  At each step, we report the potential and kinetic energies.
  The sum of these energies should be a constant.
  As an accuracy check, we also print the relative error
  in the total energy.
 
      Step      Potential       Kinetic        (P+K-E0)/E0
                Energy P        Energy K       Relative Energy Error
 
         0     498133.         0.00000         0.00000    
        40     498133.        0.502692E-01    0.168620E-10
        80     498133.        0.209009        0.155825E-10
       120     498133.        0.476361        0.120392E-10
       160     498132.        0.852441        0.504040E-11
       200     498132.         1.33741       -0.654918E-11
       240     498131.         1.93147       -0.238792E-10
       280     498130.         2.63487       -0.482070E-10
       320     498130.         3.44792       -0.806781E-10
       360     498129.         4.37097       -0.122518E-09
       400     498128.         5.40440       -0.174805E-09
 
  Elapsed cpu time for main computation:
     18.3848     seconds
 
md():
  Normal end of execution.
 
October  6 2025   6:29:55.079 PM