def calculateNewVels(coords, vels, forces, M, L, delta_t):
"""
Calculates the velocities of the current time step.
Parameters
----------
coords : numpy array
Array of the particle coordinates from the current time step.
vels : numpy array
Array of the particle velocities from the previous time step.
forces : numpy array
Array of the particle forces from the current time step.
M : int
Number of particles.
L : float
Box side length.
delta_t : float
Time step.
Returns
-------
newVels : numpy array
Array of the particle velocities from the current time step.
newForces : numpy array
Array of the particle velocities from the next time step.
"""
newForces = Task2.calculateInitialForces(M, L, coords)
newVels = numpy.full_like(vels, 0.0) # numpy array allows updates
newVels[:][:] = vels[:][:] + \
0.5 * (forces[:][:] + newForces[:][:]) * delta_t
return newVels, newForces
N : int
Number of iterations.
Returns
-------
None.
"""
filestring = Task2.createFilestring(M, L, coords, vels, "Time step 0")
for k in range(1, N):
coords = calculateNewCoords(coords, vels, forces, M, L, delta_t)
vels, forces = calculateNewVels(coords, vels, forces, M, L, delta_t)
filestring += Task2.createFilestring(M, L, coords, vels,
f"Time step {k}")
print(f"finished timestep {k}")
Task2.writeFile(filestring, "trajectories.txt")
if __name__ == "__main__":
from time import perf_counter
start = perf_counter()
path, delta_t, N = readInputArguments(sys.argv)
M, C, L, coords, vels = readFile(path)
forces = Task2.calculateInitialForces(M, L, coords)
VerletAlgorithm(coords, vels, forces, M, delta_t, N)
end = perf_counter()
print("execution time: ", end - start)
def calculateNewVels(coords, vels, forces, M, L, delta_t):
newForces = Task2.calculateInitialForces(M, L, coords)
newVels = numpy.full_like(vels, 0.0) # numpy array allows updates
newVels[:][:] = vels[:][:] + \
0.5 * (forces[:][:] + newForces[:][:]) * delta_t
return newVels, newForces
